MPEP § 2163 — MPEP § 2163
Current through: 2022-07-01

2163-Guidelines for the Examination of Patent Applications Under the 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, first paragraph,
 “Written Description” Requirement
 
 
 

 
 
 
 
 
 
 
 

 

 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 

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 Manual of Patent Examining Procedure 

 Chapter 2100 

 Section 2163 
 

 
 
 
 
 
 2163 Guidelines for the Examination of Patent Applications Under the 35
 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, first paragraph, “Written Description”
 Requirement [R-01.2024]
 

 The following Guidelines establish the policies and procedures to be
 followed by Office personnel in the evaluation of any patent application for compliance
 with the written description requirement of 35 U.S.C. 112 . These Guidelines are
 based on the Office’s current understanding of the law and are believed to be fully
 consistent with binding precedent of the U.S. Supreme Court, as well as the U.S. Court of
 Appeals for the Federal Circuit and its predecessor courts. 
 

 The Guidelines do not constitute substantive rulemaking and hence do not
 have the force and effect of law. They are designed to assist Office personnel in analyzing
 claimed subject matter for compliance with substantive law. Rejections will be based upon
 the substantive law, and it is these rejections that are appealable. Consequently, any
 perceived failure by Office personnel to follow these Guidelines is neither appealable nor
 petitionable.
 

 These Guidelines are intended to form part of the normal examination
 process. Thus, where Office personnel establish a prima facie case of
 lack of written description for a claim, a thorough review of the prior art and examination
 on the merits for compliance with the other statutory requirements, including those of
 35 U.S.C.
 101 , 102 , 103 , and
 112 , is to be conducted prior to completing an Office action that
 includes a rejection for lack of written description. 
 

 I. GENERAL PRINCIPLES GOVERNING COMPLIANCE WITH THE “WRITTEN DESCRIPTION”
 REQUIREMENT FOR APPLICATIONS 35 U.S.C.
 112(a) and the first paragraph of pre-AIA 35 U.S.C.
 112 require that the “specification shall contain a written
 description of the invention ....” This requirement is separate and distinct from the
 enablement requirement. Ariad Pharm., Inc. v. Eli Lilly & Co., 
 598 F.3d 1336, 1340, 94 USPQ2d 1161, 1167 (Fed. Cir. 2010) ( en banc );
 Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1560, 19 USPQ2d 1111,
 1114 (Fed. Cir. 1991); see also Univ. of Rochester v. G.D. Searle &
 Co., 358 F.3d 916, 920-23, 69 USPQ2d 1886, 1890-93 (Fed. Cir. 2004)
 (discussing the history and purpose of the written description requirement); In
 re Curtis, 354 F.3d 1347, 1357, 69 USPQ2d 1274, 1282 (Fed. Cir. 2004)
 (“conclusive evidence of a claim’s enablement is not equally conclusive of that claim’s
 satisfactory written description”). The written description requirement has several
 policy objectives. “[T]he ‘essential goal’ of the description of the invention
 requirement is to clearly convey the information that an applicant [inventor] has
 invented the subject matter which is claimed.” In re Barker, 559 F.2d
 588, 592 n.4, 194 USPQ 470, 473 n.4 (CCPA 1977). Another objective is to convey to the
 public what the applicant claims as the invention. See Regents of the Univ. of
 Cal. v. Eli Lilly, 119 F.3d 1559, 1566, 43 USPQ2d 1398, 1404 (Fed. Cir.
 1997), cert. denied, 523 U.S. 1089 (1998). “The ‘written description’
 requirement implements the principle that a patent must describe the technology that is
 sought to be patented; the requirement serves both to satisfy the inventor’s obligation
 to disclose the technologic knowledge upon which the patent is based, and to demonstrate
 that the patentee [inventor] was in possession of the invention that is claimed.”
 Capon v. Eshhar, 418 F.3d 1349, 1357, 76 USPQ2d 1078, 1084 (Fed.
 Cir. 2005). Further, the written description requirement promotes the progress of the
 useful arts by ensuring that patentees adequately describe their inventions in their
 patent specifications in exchange for the right to exclude others from practicing the
 invention for the duration of the patent’s term.
 

 To satisfy the written description requirement, a patent specification
 must describe the claimed invention in sufficient detail that one skilled in the art can
 reasonably conclude that the inventor had possession of the claimed invention. See,
 e.g., Moba, B.V. v. Diamond Automation, Inc., 325 F.3d 1306, 1319, 66
 USPQ2d 1429, 1438 (Fed. Cir. 2003); Vas-Cath, Inc. v. Mahurkar, 935
 F.2d at 1563, 19 USPQ2d at 1116. However, a showing of possession alone does not cure
 the lack of a written description. Enzo Biochem, Inc. v. Gen-Probe,
 Inc., 323 F.3d 956, 969-70, 63 USPQ2d 1609, 1617 (Fed. Cir. 2002). For
 example, it is now well accepted that a satisfactory description may be found in
 originally-filed claims or any other portion of the originally-filed specification. See
 In re Koller, 613 F.2d 819, 204 USPQ 702 (CCPA 1980); In
 re Gardner, 475 F.2d 1389, 177 USPQ 396 (CCPA 1973); In re
 Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). However, that does not
 mean that all originally-filed claims have adequate written support. The specification
 must still be examined to assess whether an originally-filed claim has adequate support
 in the written disclosure and/or the drawings. 
 

 An applicant shows that the inventor was in possession of the claimed
 invention by describing the claimed invention with all of its limitations using such
 descriptive means as words, structures, figures, diagrams, and formulas that fully set
 forth the claimed invention. Lockwood v. Amer. Airlines, Inc., 107
 F.3d 1565, 1572, 41 USPQ2d 1961, 1966 (Fed. Cir. 1997). Possession may be shown in a
 variety of ways including description of an actual reduction to practice, or by showing
 that the invention was “ready for patenting” such as by the disclosure of drawings or
 structural chemical formulas that show that the invention was complete, or by describing
 distinguishing identifying characteristics sufficient to show that the inventor was in
 possession of the claimed invention. See, e.g., Pfaff v. Wells Elecs.,
 Inc., 525 U.S. 55, 68, 119 S.Ct. 304, 312, 48 USPQ2d 1641, 1647 (1998);
 Eli Lilly, 119 F.3d at 1568, 43 USPQ2d at 1406; Amgen,
 Inc. v. Chugai Pharm., 927 F.2d 1200, 1206, 18 USPQ2d 1016, 1021 (Fed. Cir.
 1991) (one must define a compound by “whatever characteristics sufficiently distinguish
 it”). “Compliance with the written description requirement is essentially a fact-based
 inquiry that will ‘necessarily vary depending on the nature of the invention claimed.’”
 Enzo Biochem, 323 F.3d at 963, 63 USPQ2d at 1612. An application
 specification may show actual reduction to practice by describing testing of the claimed
 invention or, in the case of certain biological materials, by specifically describing a
 deposit made in accordance with 37 CFR 1.801 et seq. See Enzo Biochem, 323 F.3d at 965, 63
 USPQ2d at 1614 (“reference in the specification to a deposit may also satisfy the
 written description requirement with respect to a claimed material”); see also Deposit
 of Biological Materials for Patent Purposes, Final Rule, 54 Fed. Reg. 34,864 (August 22,
 1989) (“The requirement for a specific identification is consistent with the description
 requirement of the first paragraph of 35 U.S.C. 112 , and to provide an
 antecedent basis for the biological material which either has been or will be deposited
 before the patent is granted.” Id. at 34,876. “The description must
 be sufficient to permit verification that the deposited biological material is in fact
 that disclosed. Once the patent issues, the description must be sufficient to aid in the
 resolution of questions of infringement.” Id. at 34,880.) Such a
 deposit is not a substitute for a written description of the claimed invention. The
 written description of the deposited material needs to be as complete as possible
 because the examination for patentability proceeds solely on the basis of the written
 description. See, e.g., In re Lundak, 773 F.2d 1216, 227 USPQ 90
 (Fed. Cir. 1985); see also 54 Fed. Reg. at 34,880 (“As a general rule, the more
 information that is provided about a particular deposited biological material, the
 better the examiner will be able to compare the identity and characteristics of the
 deposited biological material with the prior art.”).
 

 A question as to whether a specification provides an adequate written
 description may arise in the context of determining whether an original claim is
 described sufficiently (see, e.g., LizardTech, Inc. v. Earth Resource Mapping,
 Inc., 424 F.3d 1336, 1345, 76 USPQ2d 1724, 1733 (Fed. Cir. 2005);
 Enzo Biochem, 323 F.3d at 968, 63 USPQ2d at 1616 (Fed. Cir. 2002);
 Eli Lilly, 119 F.3d 1559, 43 USPQ2d 1398)), whether new or amended
 claims are supported by the description of the invention in the application as filed
 (see, e.g., In re Wright, 866 F.2d 422, 9 USPQ2d 1649 (Fed. Cir.
 1989)), whether a claimed invention is entitled to the benefit of or priority to an
 earlier filing date under 35 U.S.C. 119 , 120 ,
 365 , or 386 (see, e.g., New
 Railhead Mfg. L.L.C. v. Vermeer Mfg. Co., 298 F.3d 1290, 63 USPQ2d 1843
 (Fed. Cir. 2002); Tronzo v. Biomet, Inc., 156 F.3d 1154, 47 USPQ2d
 1829 (Fed. Cir. 1998); Fiers v. Revel, 984 F.2d 1164, 25 USPQ2d 1601
 (Fed. Cir. 1993); In re Ziegler, 992 F.2d 1197, 1200, 26 USPQ2d 1600,
 1603 (Fed. Cir. 1993)), or whether a specification provides support for a claim
 corresponding to a count in an interference (see, e.g., Martin v.
 Mayer, 823 F.2d 500, 503, 3 USPQ2d 1333, 1335 (Fed. Cir. 1987);
 Fields v. Conover, 443 F.2d 1386, 170 USPQ 276 (CCPA 1971)).
 Compliance with the written description requirement is a question of fact which must be
 resolved on a case-by-case basis. Vas-Cath, Inc. v. Mahurkar, 935
 F.2d at 1563, 19 USPQ2d at 1116 (Fed. Cir. 1991).
 

 A. Original Claims There is a presumption that an adequate written description of the
 claimed invention is present when the application is filed. In re
 Wertheim, 541 F.2d 257, 263, 191 USPQ 90, 97 (CCPA 1976) (“[W]e are of
 the opinion that the PTO has the initial burden of presenting evidence or reasons why
 persons skilled in the art would not recognize in the disclosure a description of the
 invention defined by the claims.”). However, as discussed in subsection I,
 supra, issues of adequate written description may arise even
 for original claims, for example, when an aspect of the claimed invention has not
 been described with sufficient particularity such that one skilled in the art would
 recognize that the inventor had possession of the claimed invention at the time of
 filing. The claimed invention as a whole may not be adequately described if the
 claims require an essential or critical feature which is not adequately described in
 the specification and which is not conventional or known in the art. Consider the
 claim “A gene comprising SEQ ID NO:1.” The claim may be construed to include specific
 structures in addition to SEQ ID NO:1, such as a promoter, a coding region, or other
 elements. Although SEQ ID NO:1 is fully disclosed, there may be insufficient
 description of other structures embraced by the claim (e.g., promoters, enhancers,
 coding regions, and other regulatory elements). For guidance on subject matter
 eligibility of such claims, see MPEP § 2106 .
 

 An invention described solely in terms of a method of making and/or
 its function may lack written descriptive support where there is no described or
 art-recognized correlation between the disclosed function and the structure(s)
 responsible for the function. For example, the amino acid sequence of a protein along
 with knowledge of the genetic code might put an inventor in possession of the genus
 of nucleic acids capable of encoding the protein, but the same information would not
 place the inventor in possession of the naturally-occurring DNA or mRNA encoding the
 protein. See In re Bell, 991 F.2d 781, 26 USPQ2d 1529 (Fed. Cir.
 1993); In re Deuel, 51 F.3d 1552, 34 USPQ2d 1210 (Fed. Cir. 1995)
 (holding that a process could not render the product of that process obvious under
 35 U.S.C.
 103 ). (For guidance on subject matter eligibility of claims to
 naturally-occurring compositions, see MPEP § 2106 .) The Federal Circuit
 has pointed out that, under United States law, a description that merely renders a
 claimed invention obvious may not sufficiently describe the invention for the
 purposes of the written description requirement of 35 U.S.C. 112 .
 See Eli Lilly, 119 F.3d at 1567, 43 USPQ2d at 1405; compare
 Fonar Corp. v. Gen. Elec. Co., 107 F.3d 1543, 1549, 41 USPQ2d
 1801, 1805 (Fed. Cir. 1997) (“As a general rule, where software constitutes part of a
 best mode of carrying out an invention, description of such a best mode is satisfied
 by a disclosure of the functions of the software. This is because, normally, writing
 code for such software is within the skill of the art, not requiring undue
 experimentation, once its functions have been disclosed.... Thus, flow charts or
 source code listings are not a requirement for adequately disclosing the functions of
 software.”).
 

 Written description issues may also arise if the knowledge and level
 of skill in the art would not have permitted the ordinary artisan to immediately
 envisage the claimed product arising from the disclosed process. See, e.g., 
 Fujikawa v. Wattanasin, 93 F.3d 1559, 1571, 39 USPQ2d 1895, 1905 (Fed.
 Cir. 1996) (a “laundry list” disclosure of every possible moiety does not necessarily
 constitute a written description of every species in a genus because it would not
 “reasonably lead” those skilled in the art to any particular species); In re
 Ruschig, 379 F.2d 990, 995, 154 USPQ 118, 123 (CCPA 1967)
 (“ If n-propylamine had been used in making the compound instead
 of n-butylamine, the compound of claim 13 would have resulted. Appellants submit to
 us, as they did to the board, an imaginary specific example patterned on specific
 example 6 by which the above butyl compound is made so that we can see what a simple
 change would have resulted in a specific supporting disclosure being present in the
 present specification. The trouble is that there is no such disclosure, easy though
 it is to imagine it.” (emphasis in original)); Purdue Pharma L.P. v.
 Faulding Inc., 230 F.3d 1320, 1328, 56 USPQ2d 1481, 1487 (Fed. Cir.
 2000) (“[T]he specification does not clearly disclose to the skilled artisan that the
 inventors ... considered the ratio... to be part of their invention .... There is
 therefore no force to Purdue’s argument that the written description requirement was
 satisfied because the disclosure revealed a broad invention from which the
 [later-filed] claims carved out a patentable portion”).
 

 B. New or Amended Claims The proscription against the introduction of new matter in a patent
 application ( 35
 U.S.C. 132 and 251 ) serves to prevent an
 applicant from adding information that goes beyond the subject matter originally
 filed. See In re Rasmussen, 650 F.2d 1212, 1214, 211 USPQ 323, 326
 (CCPA 1981); see also MPEP §§ 2163.06 through 2163.07 for a more
 detailed discussion of the written description requirement and its relationship to
 new matter. The claims as filed in the original specification are part of the
 disclosure and, therefore, if an application as originally filed contains a claim
 disclosing material not found in the remainder of the specification, the applicant
 may amend the specification to include the claimed subject matter. In re
 Benno, 768 F.2d 1340, 226 USPQ 683 (Fed. Cir. 1985). Thus, the written
 description requirement prevents an applicant from claiming subject matter that was
 not adequately described in the specification as filed. New or amended claims which
 introduce elements or limitations that are not supported by the as-filed disclosure
 violate the written description requirement. See, e.g., In re
 Lukach, 442 F.2d 967, 169 USPQ 795 (CCPA 1971) (subgenus range was not
 supported by generic disclosure and specific example within the subgenus range);
 In re Smith, 458 F.2d 1389, 1395, 173 USPQ 679, 683 (CCPA 1972)
 (an adequate description of a genus may not support claims to a subgenus or species
 within the genus).
 

 While there is no in haec verba requirement,
 newly added claims or claim limitations must be supported in the specification
 through express, implicit, or inherent disclosure. An amendment to correct an obvious
 error does not constitute new matter where the ordinary artisan would not only
 recognize the existence of the error in the specification, but also recognize the
 appropriate correction. In re Oda, 443 F.2d 1200, 170 USPQ 268
 (CCPA 1971). With respect to the correction of sequencing errors in applications
 disclosing nucleic acid and/or amino acid sequences, it is well known that sequencing
 errors are a common problem in molecular biology. See, e.g., David Laehnemann
 et al., Denoising DNA deep sequencing data—high-throughput
 sequencing errors and their correction, 17 Briefings in
 Bioinformatics 154–1791 (2016); Peter Richterich, Estimation of Errors
 in ‘Raw’ DNA Sequences: A Validation Study, 8 Genome Research 
 251-59 (1998). For example, if an application as filed includes incorrect nucleic
 acid sequence information and references a deposit of the sequenced material made in
 accordance with the requirements of 37 CFR 1.801 et seq., an amendment to correct the nucleic acid sequence may be
 permissible where the amendment conforms the sequence information to the compound
 described in the specification and covered by the claims. See Cubist Pharm.,
 Inc. v. Hospira, Inc., 805 F.3d 1112, 1118, 117 USPQ2d 1054, 1059 (Fed.
 Cir. 2015)(“The fact that the inventors were mistaken as to one aspect of the
 structure of daptomycin at the time the application [ ] was filed does not render the
 specification inadequate to satisfy the written description requirement. It was
 enough that the specification disclosed relevant identifying characteristics that
 distinguished daptomycin from other compounds and thus showed that the inventors had
 possession of daptomycin, even though they may not have had an accurate picture of
 the entire chemical structure of that compound.” Id. at 1120, 117
 USPQ2d at 1060.) Deposits made after the filing date may be relied upon to provide
 support for the correction of sequence information only if applicant submits a
 statement in compliance with 37 CFR 1.804 stating that the
 biological material which is deposited is the biological material specifically
 defined in the application as filed.
 

 Under certain circumstances, omission of a limitation can raise an
 issue regarding whether the inventor had possession of a broader, more generic
 invention. See, e.g., PIN/NIP, Inc. v. Platte Chem. Co., 304 F.3d
 1235, 1248, 64 USPQ2d 1344, 1353 (Fed. Cir. 2002) (Claim for a method of inhibiting
 sprout growth on tubers by treating them with spaced, sequential
 application of two chemicals was held invalid for lack of adequate written
 description where the specification indicated that invention was a method of applying
 a "composition" containing the two chemicals.); Gentry
 Gallery, Inc. v. Berkline Corp., 134 F.3d 1473, 45 USPQ2d 1498 (Fed.
 Cir. 1998) (claims to a sectional sofa comprising, inter alia, a
 console and a control means were held invalid for failing to satisfy the written
 description requirement where the claims were broadened by removing the location of
 the control means); Johnson Worldwide Assoc. v. Zebco Corp., 175
 F.3d 985, 993, 50 USPQ2d 1607, 1613 (Fed. Cir. 1999) (stating that, in
 Gentry Gallery, the “court’s determination that the patent
 disclosure did not support a broad meaning for the disputed claim terms was premised
 on clear statements in the written description that described the location of a claim
 element--the ‘control means’ --as ‘the only possible location’ and that variations
 were ‘outside the stated purpose of the invention.’ … Gentry
 Gallery, then, considers the situation where the patent’s disclosure
 makes crystal clear that a particular (i.e., narrow) understanding of a claim term is
 an ‘essential element of [the inventor’s] invention.’”); see also Tronzo v.
 Biomet, 156 F.3d at 1158-59, 47 USPQ2d at 1833 (Fed. Cir. 1998) (claims
 to generic cup shape were not entitled to filing date of parent application which
 disclosed “conical cup” in view of the disclosure of the parent application stating
 the advantages and importance of the conical shape.). A claim that omits an element
 that applicant describes as an essential or critical feature of the invention
 originally disclosed does not comply with the written description requirement. See
 Gentry Gallery, 134 F.3d at 1480, 45 USPQ2d at 1503;
 In re Sus, 306 F.2d 494, 504, 134 USPQ 301, 309 (CCPA 1962)
 (“[O]ne skilled in this art would not be taught by the written description of the
 invention in the specification that any ‘aryl or substituted aryl radical’ would be
 suitable for the purposes of the invention but rather that only certain aryl
 radicals and certain specifically substituted aryl radicals [i.e., aryl
 azides] would be suitable for such purposes.”(emphasis in original)). A claim which
 omits matter disclosed to be essential to the invention as described in the
 specification or in other statements of record may also be subject to rejection under
 35
 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, as not enabling, or under 35 U.S.C. 112(b) or
 pre-AIA
 35 U.S.C. 112 , second paragraph. See In re
 Mayhew, 527 F.2d 1229, 188 USPQ 356 (CCPA 1976); In re
 Venezia, 530 F.2d 956, 189 USPQ 149 (CCPA 1976); and In re
 Collier, 397 F.2d 1003, 158 USPQ 266 (CCPA 1968). See also
 MPEP
 § 2172.01 .
 

 The fundamental factual inquiry is whether the specification conveys
 with reasonable clarity to those skilled in the art that, as of the filing date
 sought, the inventor was in possession of the invention as now claimed. See, e.g.,
 Vas-Cath, Inc., 935 F.2d at 1563-64, 19 USPQ2d at 1117.
 

 II. METHODOLOGY FOR DETERMINING ADEQUACY OF WRITTEN DESCRIPTION 
 

 A. Read and Analyze the Specification for Compliance with 35 U.S.C. 112(a)
 or Pre-AIA 35 U.S.C. 112, first paragraph Office personnel should adhere to the following procedures when
 reviewing patent applications for compliance with the written description requirement
 of 35
 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph. There is a presumption that an adequate written description of the claimed
 invention is present in the specification as filed, Wertheim, 541
 F.2d at 262, 191 USPQ at 96, thus the examiner has the initial burden, after a
 thorough reading and evaluation of the content of the application, of presenting
 evidence or reasons why a person skilled in the art would not recognize the written
 description of the invention as providing adequate support for the claimed invention.
 To make a prima facie case, it is necessary to identify the claim
 limitations that are not adequately supported, and explain why the claim is not fully
 supported by the disclosure. For example, in Hyatt v. Dudas, 492
 F.3d 1365, 1371, 83 USPQ2d 1373, 1376-1377 (Fed. Cir. 2007), the examiner made a
 prima facie case by clearly and specifically explaining why
 applicant’s specification did not support the particular claimed combination of
 elements, even though applicant’s specification listed each and every element in the
 claimed combination. The court found the “examiner was explicit that while each
 element may be individually described in the specification, the deficiency was lack
 of adequate description of their combination” and, thus, “[t]he burden was then
 properly shifted to [inventor] to cite to the examiner where adequate written
 description could be found or to make an amendment to address the deficiency.”
 Id.; see also Stored Value Solutions, Inc. v. Card
 Activation Techs., 499 Fed.App’x 5, 13-14 (Fed. Cir. 2012)
 (non-precedential) (Finding inadequate written support for claims drawn to a method
 of processing debit purchase transactions requiring three separate authorization
 codes because “the written description [did] not contain a method that include[d] all
 three codes” and “[e]ach authorization code is an important claim limitation, and the
 presence of multiple authorization codes in [the claim] was essential”.). 
 

 With respect to newly added or amended claims,
 applicant should show support in the original disclosure for the new or amended
 claims. See, e.g., Hyatt v. Dudas, 492 F.3d 1365, 1370, n.4, 83
 USPQ2d 1373, 1376, n.4 (Fed. Cir. 2007) (citing MPEP § 2163.04 
 which provides that a “simple statement such as ‘applicant has not pointed out where
 the new (or amended) claim is supported, nor does there appear to be a written
 description of the claim limitation ‘___’ in the application as filed’ may be
 sufficient where the claim is a new or amended claim, the support for the limitation
 is not apparent, and applicant has not pointed out where the limitation is
 supported.”); see also MPEP §§ 714.02 and 2163.06 (“Applicant should ...
 specifically point out the support for any amendments made to the disclosure.”); and
 MPEP §
 2163.04 (“If applicant amends the claims and points out
 where and/or how the originally filed disclosure supports the amendment(s), and the
 examiner finds that the disclosure does not reasonably convey that the inventor had
 possession of the subject matter of the amendment at the time of the filing of the
 application, the examiner has the initial burden of presenting evidence or reasoning
 to explain why persons skilled in the art would not recognize in the disclosure a
 description of the invention defined by the claims.”). The inquiry into whether the
 description requirement is met is a question of fact that must be determined on a
 case-by-case basis. AbbVie Deutschland GmbH & Co., KG v. Janssen
 Biotech, Inc., 759 F.3d 1285, 1297, 111 USPQ2d 1780, 1788 (Fed. Cir.
 2014) ("Whether a patent claim is supported by an adequate written description is a
 question of fact."); In re Smith, 458 F.2d 1389, 1395, 173 USPQ
 679, 683 (CCPA 1972) (“Precisely how close [to the claimed invention] the description
 must come to comply with Sec. 112 must be left to case-by-case development.”);
 In re Wertheim, 541 F.2d at 262, 191 USPQ at 96 (inquiry is
 primarily factual and depends on the nature of the invention and the amount of
 knowledge imparted to those skilled in the art by the disclosure).
 

 1. For Each Claim, Determine What the Claim as a Whole Covers Claim construction is an essential part of the examination
 process. Each claim must be separately analyzed and given its broadest reasonable
 interpretation in light of and consistent with the written description. See, e.g.,
 In re Katz Interactive Call Processing Patent Litigation, 
 639 F.3d 1303, 1319-1320, 97 USPQ2d 1737, 1750 (Fed. Cir. 2011) (stating that
 “[t]he construction of the claims [is] important to the written description
 analysis” and patent holder’s failure “to point to a genuine factual dispute over
 whether the specification disclosed” the claimed subject matter made summary
 judgment proper on that issue.); In re Morris, 127 F.3d 1048,
 1053-54, 44 USPQ2d 1023, 1027 (Fed. Cir. 1997). The entire claim must be
 considered, including the preamble language and the transitional phrase. “Preamble
 language” is that language in a claim appearing before the transitional phase,
 e.g., before “comprising,” “consisting essentially of,” or “consisting of.” The
 transitional term “comprising” (and other comparable terms, e.g., “containing,”
 and “including”) is “open-ended” in that it covers the expressly recited subject
 matter, alone or in combination with unrecited subject matter. See, e.g.,
 Genentech, Inc. v. Chiron Corp., 112 F.3d 495, 501, 42
 USPQ2d 1608, 1613 (Fed. Cir. 1997) (“‘Comprising’ is a term of art used in claim
 language which means that the named elements are essential, but other elements may
 be added and still form a construct within the scope of the claim.”); Ex
 parte Davis, 80 USPQ 448, 450 (Bd. App. 1948) (“comprising” leaves
 the “claim open for the inclusion of unspecified ingredients even in major
 amounts”); see also MPEP § 2111.03 . “By using the term ‘consisting
 essentially of,’ the drafter signals that the invention necessarily includes the
 listed ingredients and is open to unlisted ingredients that do not materially
 affect the basic and novel properties of the invention. A ‘consisting essentially
 of’ claim occupies a middle ground between closed claims that are written in a
 ‘consisting of’ format and fully open claims that are drafted in a ‘comprising’
 format.” PPG Indus. v. Guardian Indus., 156 F.3d 1351, 1354, 48
 USPQ2d 1351, 1353-54 (Fed. Cir. 1998). For the purposes of searching for and
 applying prior art under 35 U.S.C. 102 and
 103 , absent a clear indication in the specification or
 claims of what the basic and novel characteristics actually are, “consisting
 essentially of” will be construed as equivalent to “comprising.” See, e.g.,
 PPG, 156 F.3d at 1355, 48 USPQ2d at 1355 (“PPG could have
 defined the scope of the phrase ‘consisting essentially of’ for purposes of its
 patent by making clear in its specification what it regarded as constituting a
 material change in the basic and novel characteristics of the invention.”); see
 also AK Steel Corp. v. Sollac, 344 F3.d 1234, 1239-1240, 68
 USPQ2d 1280, 1283-84 (Fed. Cir. 2003); In re Janakirama-Rao, 
 317 F.2d 951, 954, 137 USPQ 893, 895-96 (CCPA 1963). If an applicant contends that
 additional steps or materials in the prior art are excluded by the recitation of
 “consisting essentially of,” applicant has the burden of showing that the
 introduction of additional steps or components would materially change the
 characteristics of the claimed invention. In re De Lajarte, 337
 F.2d 870, 143 USPQ 256 (CCPA 1964); see also MPEP § 2111.03 .
 The claim as a whole, including all limitations found in the preamble (see
 Pac-Tec Inc. v. Amerace Corp., 903 F.2d 796, 801, 14 USPQ2d
 1871, 1876 (Fed. Cir. 1990) (determining that preamble language that constitutes a
 structural limitation is actually part of the claimed invention)), the
 transitional phrase, and the body of the claim, must be sufficiently supported to
 satisfy the written description requirement. An applicant shows that the inventor
 was in possession of the claimed invention by describing the claimed invention
 with all of its limitations. Lockwood, 107 F.3d at 1572,
 41 USPQ2d at 1966.
 

 The examiner should evaluate each claim to determine if
 sufficient structures, acts, or functions are recited to make clear the scope and
 meaning of the claim, including the weight to be given the preamble. See, e.g.,
 Bell Communications Research, Inc. v. Vitalink Communications
 Corp., 55 F.3d 615, 620, 34 USPQ2d 1816, 1820 (Fed. Cir. 1995) (“[A]
 claim preamble has the import that the claim as a whole suggests for it.”);
 Corning Glass Works v. Sumitomo Elec. U.S.A., Inc., 868 F.2d
 1251, 1257, 9 USPQ2d 1962, 1966 (Fed. Cir. 1989) (The determination of whether
 preamble recitations are structural limitations can be resolved only on review of
 the entirety of the application “to gain an understanding of what the inventors
 actually invented and intended to encompass by the claim.”). The absence of
 definitions or details for well-established terms or procedures should not be the
 basis of a rejection under 35 U.S.C. 112(a) or
 pre-AIA 35
 U.S.C. 112 , first paragraph, for lack of adequate written
 description. Limitations may not, however, be imported into the claims from the
 specification.
 

 2. Review the Entire Application to Understand How Applicant Provides Support
 for the Claimed Invention Including Each Element and/or Step Prior to determining whether the disclosure provides adequate
 written description for the claimed subject matter, the examiner should review the
 claims and the entire specification, including the specific embodiments, figures,
 and sequence listings, to understand how applicant provides support for the
 various features of the claimed invention. The disclosure of an element may be
 critical where those of ordinary skill in the art would require it to understand
 that inventor was in possession of the invention. Compare
 Rasmussen, 650 F.2d at 1215, 211 USPQ at 327 (“one skilled
 in the art who read Rasmussen’s specification would understand that it is
 unimportant how the layers are adhered, so long as they are adhered”) (emphasis in
 original), with Amgen, Inc. v. Chugai Pharm.Co., Ltd., 927 F.2d
 1200, 1206, 18 USPQ2d 1016, 1021 (Fed. Cir. 1991) (“it is well established in our
 law that conception of a chemical compound requires that the inventor be able to
 define it so as to distinguish it from other materials, and to describe how to
 obtain it”). The analysis of whether the specification complies with the written
 description requirement calls for the examiner to compare the scope of the claim
 with the scope of the description to determine whether applicant has demonstrated
 that the inventor was in possession of the claimed invention. Such a review is
 conducted from the standpoint of one of ordinary skill in the art at the time the
 application was filed (see, e.g., Wang Labs., Inc. v. Toshiba
 Corp., 993 F.2d 858, 865, 26 USPQ2d 1767, 1774 (Fed. Cir. 1993)) and
 should include a determination of the field of the invention and the level of
 skill and knowledge in the art. For some arts, there is an inverse correlation
 between the level of skill and knowledge in the art and the specificity of
 disclosure necessary to satisfy the written description requirement. Information
 which is well known in the art need not be described in detail in the
 specification. See, e.g., Hybritech, Inc. v. Monoclonal Antibodies,
 Inc., 802 F.2d 1367, 1379-80, 231 USPQ 81, 90 (Fed. Cir. 1986).
 However, sufficient information must be provided to show that the inventor had
 possession of the invention as claimed.
 

 3. Determine Whether There is Sufficient Written Description to Inform a
 Skilled Artisan That Inventor was in Possession of the Claimed Invention as a
 Whole at the Time the Application Was Filed 
 

 (a) Original claims Possession may be shown in many ways. For example, possession
 may be shown by describing an actual reduction to practice of the claimed
 invention. Possession may also be shown by a clear depiction of the invention
 in detailed drawings or in structural chemical formulas which permit a person
 skilled in the art to clearly recognize that inventor had possession of the
 claimed invention. An adequate written description of the invention may be
 shown by any description of sufficient, relevant, identifying characteristics
 so long as a person skilled in the art would recognize that the inventor had
 possession of the claimed invention. See, e.g., Purdue Pharma L.P. v.
 Faulding Inc., 230 F.3d 1320, 1323, 56 USPQ2d 1481, 1483 (Fed.
 Cir. 2000) (the written description “inquiry is a factual one and must be
 assessed on a case-by-case basis”); see also Pfaff v. Wells Elec.,
 Inc., 55 U.S. at 66, 119 S.Ct. at 311, 48 USPQ2d at 1646 (“The
 word ‘invention’ must refer to a concept that is complete, rather than merely
 one that is ‘substantially complete.’ It is true that reduction to practice
 ordinarily provides the best evidence that an invention is complete. But just
 because reduction to practice is sufficient evidence of completion, it does not
 follow that proof of reduction to practice is necessary in every case. Indeed,
 both the facts of the Telephone Cases and the facts of this case demonstrate
 that one can prove that an invention is complete and ready for patenting before
 it has actually been reduced to practice.”).
 

 A specification may describe an actual reduction to practice
 by showing that the inventor constructed an embodiment or performed a process
 that met all the limitations of the claim and determined that the invention
 would work for its intended purpose. Cooper v. Goldfarb, 154
 F.3d 1321, 1327, 47 USPQ2d 1896, 1901 (Fed. Cir. 1998). See also UMC
 Elecs. Co. v. United States, 816 F.2d 647, 652, 2 USPQ2d 1465,
 1468 (Fed. Cir. 1987) (“[T]here cannot be a reduction to practice of the
 invention ... without a physical embodiment which includes all limitations of
 the claim.”); Estee Lauder Inc. v. L’Oreal, S.A., 129 F.3d
 588, 593, 44 USPQ2d 1610, 1614 (Fed. Cir. 1997) (“[A] reduction to practice
 does not occur until the inventor has determined that the invention will work
 for its intended purpose.”); Mahurkar v. C.R. Bard, Inc., 79
 F.3d 1572, 1578, 38 USPQ2d 1288, 1291 (Fed. Cir. 1996) (determining that the
 invention will work for its intended purpose may require testing depending on
 the character of the invention and the problem it solves). Description of an
 actual reduction to practice of a biological material may be shown by
 specifically describing a deposit made in accordance with the requirements of
 37 CFR
 1.801 et seq., especially 37 CFR 1.804 and
 1.809 ; see also subsection I. supra. 

 An applicant may show that the inventor was in possession of
 an invention by disclosure of drawings or structural chemical formulas that are
 sufficiently detailed to show that the inventor was in possession of the
 claimed invention as a whole. See, e.g., Vas-Cath, 935 F.2d
 at 1565, 19 USPQ2d at 1118 (“drawings alone may provide a ‘written description’
 of an invention as required by Sec. 112 ”); In re
 Wolfensperger, 302 F.2d 950, 133 USPQ 537 (CCPA 1962) (the
 drawings of applicant’s specification provided sufficient written descriptive
 support for the claim limitation at issue); Autogiro Co. of Am. v.
 United States, 384 F.2d 391, 398, 155 USPQ 697, 703 (Ct. Cl. 1967)
 (“In those instances where a visual representation can flesh out words,
 drawings may be used in the same manner and with the same limitations as the
 specification.”); Eli Lilly, 119 F.3d at 1568, 43 USPQ2d at
 1406 (“In claims involving chemical materials, generic formulae usually
 indicate with specificity what the generic claims encompass. One skilled in the
 art can distinguish such a formula from others and can identify many of the
 species that the claims encompass. Accordingly, such a formula is normally an
 adequate description of the claimed genus.”). The description need only
 describe in detail that which is new or not conventional. See
 Hybritech v. Monoclonal Antibodies, 802 F.2d at 1384, 231
 USPQ at 94. This is equally true whether the claimed invention is directed to a
 product or a process.
 

 An applicant may also show that an invention is complete by
 disclosure of sufficiently detailed, relevant identifying characteristics which
 provide evidence that inventor was in possession of the claimed invention,
 i.e., complete or partial structure, other physical and/or chemical properties,
 functional characteristics when coupled with a known or disclosed correlation
 between function and structure, or some combination of such characteristics.
 Enzo Biochem, 323 F.3d at 964, 63 USPQ2d at 1613 (quoting
 the Written Description Guidelines, 66 Fed. Reg. at 1106, n. 49, stating that
 “if the art has established a strong correlation between structure and
 function, one skilled in the art would be able to predict with a reasonable
 degree of confidence the structure of the claimed invention from a recitation
 of its function”.). “Thus, the written description requirement may be satisfied
 through disclosure of function and minimal structure when there is a
 well-established correlation between structure and function.”
 Id. 

 For some biomolecules, examples of identifying characteristics
 include a sequence, structure, binding affinity, binding specificity, molecular
 weight, and length. Although structural formulas provide a convenient method of
 demonstrating possession of specific molecules, other identifying
 characteristics or combinations of characteristics may demonstrate the
 requisite possession. As explained by the Federal Circuit, “(1) examples are
 not necessary to support the adequacy of a written description; (2) the written
 description standard may be met … even where actual reduction to practice of an
 invention is absent; and (3) there is no per se rule that an adequate written
 description of an invention that involves a biological macromolecule must
 contain a recitation of known structure.” Falkner v. Inglis, 
 448 F.3d 1357, 1366, 79 USPQ2d 1001, 1007 (Fed. Cir. 2006); see also
 Capon v. Eshhar, 418 F.3d at 1358, 76 USPQ2d at 1084
 (“The Board erred in holding that the specifications do not meet the written
 description requirement because they do not reiterate the structure or formula
 or chemical name for the nucleotide sequences of the claimed chimeric genes”
 where the genes were novel combinations of known DNA segments.). However, the
 claimed invention itself must be adequately described in the written disclosure
 and/or the drawings. For example, disclosure of an antigen fully characterized
 by its structure, formula, chemical name, physical properties, or deposit in a
 public depository does not, without more, provide an adequate written
 description of an antibody claimed by its binding affinity to that antigen,
 even when preparation of such an antibody is routine and conventional. See
 Amgen Inc. v. Sanofi, 872 F.3d 1367, 1378, 124 USPQ2d
 1354, 1361 (Fed. Cir. 2017)(“knowledge of the chemical structure of an antigen
 [does not give] the required kind of structure-identifying information about
 the corresponding antibodies”); see also Centocor Ortho Biotech, Inc.
 v. Abbott Labs., 636 F.3d 1341, 1351-52, 97 USPQ2d 1870, 1877
 (Fed. Cir. 2011)(patent disclosed the antigen the claimed antibody was supposed
 to bind, but did not disclose any antibodies with the specific claimed
 properties). 
 

 Other ways of establishing possession of a
 claimed invention may include unique cleavage by particular enzymes,
 isoelectric points of fragments, detailed restriction enzyme maps, a comparison
 of enzymatic activities, or antibody cross-reactivity. See
 Lockwood, 107 F.3d at 1572, 41 USPQ2d at 1966 (Stating
 that the written description requirement may be satisfied by using “such
 descriptive means as words, structures, figures, diagrams, formulas, etc., that
 fully set forth the claimed invention.”). Conversely, describing a composition
 by its function alone typically will not suffice to sufficiently describe the
 composition. See Eli Lilly, 119 F.3 at 1568, 43 USPQ2d at
 1406 (Holding that description of a gene’s function will not enable claims to
 the gene “because it is only an indication of what the gene does, rather than
 what it is.”); see also Fiers, 984 F.2d at 1169-71, 25
 USPQ2d at 1605-06 (discussing Amgen Inc. v. Chugai Pharm.
 Co., 927 F.2d 1200, 18 USPQ2d 1016 (Fed. Cir. 1991)). An adequate
 written description of a chemical invention also requires a precise definition,
 such as by structure, formula, chemical name, or physical properties, and not
 merely a wish or plan for obtaining the chemical invention claimed. See, e.g.,
 Univ. of Rochester v. G.D. Searle & Co., 358 F.3d
 916, 927, 69 USPQ2d 1886, 1894-95 (Fed. Cir. 2004) (The patent at issue claimed
 a method of selectively inhibiting PGHS-2 activity by administering a
 non-steroidal compound that selectively inhibits activity of the PGHS-2 gene
 product, however the patent did not disclose any compounds that can be used in
 the claimed methods. While there was a description of assays for screening
 compounds to identify those that inhibit the expression or activity of the
 PGHS-2 gene product, there was no disclosure of which peptides,
 polynucleotides, and small organic molecules selectively inhibit PGHS-2. The
 court held that “[w]ithout such disclosure, the claimed methods cannot be said
 to have been described.”).
 

 If a claim limitation invokes 35 U.S.C.
 112(f) or pre-AIA 35 U.S.C. 112 ,
 sixth paragraph, it must be interpreted to cover the corresponding structure,
 materials, or acts in the specification and “equivalents thereof.” See
 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112 ,
 sixth paragraph. See also B. Braun Medical, Inc. v. Abbott
 Labs., 124 F.3d 1419, 1424, 43 USPQ2d 1896, 1899 (Fed. Cir. 1997).
 In considering whether there is 35 U.S.C. 112(a) or
 pre-AIA 35
 U.S.C. 112 , first paragraph, support for a means- (or
 step) plus- function claim limitation, the examiner must consider not only the
 original disclosure contained in the summary and detailed description of the
 invention portions of the specification, but also the original claims,
 abstract, and drawings. A means- (or step-) plus- function claim limitation is
 adequately described under 35 U.S.C. 112(a) or
 pre-AIA 35
 U.S.C. 112 , first paragraph, if: (1) The written
 description adequately links or associates adequately described particular
 structure, material, or acts to perform the function recited in a means- (or
 step-) plus- function claim limitation; or (2) it is clear based on the facts
 of the application that one skilled in the art would have known what structure,
 material, or acts disclosed in the specification perform the function recited
 in a means- (or step-) plus- function limitation. See Aristocrat
 Techs. Australia PTY Ltd. v. Int’l Game Tech., 521 F.3d 1328,
 1336-37, 86 USPQ2d 1235, 1242 (Fed. Cir. 2008) (“'consideration of the
 understanding of one skilled in the art in no way relieves the patentee of
 adequately disclosing sufficient structure in the specification.’ It is not
 enough for the patentee simply to state or later argue that persons of ordinary
 skill in the art would know what structures to use to accomplish the claimed
 function.”), quoting Atmel Corp. v. Information Storage Devices,
 Inc., 198 F.3d 1374, 1380, 53 USPQ2d 1225, 1229 (Fed. Cir. 1999);
 Biomedino, LLC v. Waters Technologies Corp., 490 F.3d
 946, 953, 83 USPQ2d 1118, 1123 (Fed. Cir. 2007) (“The inquiry is whether one of
 skill in the art would understand the specification itself to disclose a
 structure, not simply whether that person would be capable of implementing a
 structure."). Note also that a rejection under 35 U.S.C.
 112(b) or pre-AIA 35 U.S.C. 112 ,
 second paragraph, “cannot stand where there is adequate description in the
 specification to satisfy 35 U.S.C. 112(a) or
 pre-AIA 35
 U.S.C. 112 , first paragraph, regarding
 means-plus-function recitations that are not, per se, challenged for being
 unclear.” In re Noll, 545 F.2d 141, 149, 191 USPQ 721, 727
 (CCPA 1976). See "Supplemental Examination Guidelines for Determining the
 Applicability of 35 U.S.C. 112 , para. 6,"
 65 Fed. Reg. 38510, June 21, 2000; see also MPEP § 2181 .
 However, when a means- (or step-) plus-function claim limitation is found to be
 indefinite based on failure of the specification to disclose sufficient
 corresponding structure, materials, or acts that perform the entire claimed
 function, then the claim limitation necessarily lacks an adequate written
 description. Thus, when a claim is rejected as indefinite under
 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112 ,
 second paragraph because there is no corresponding structure, materials, or
 acts, or an inadequate disclosure of corresponding structure, materials, or
 acts, for a means- (or step-) plus-function claim limitation, then the claim
 must also be rejected under 35 U.S.C. 112(a) or
 pre-AIA 35
 U.S.C. 112 , first paragraph, for lack of an adequate
 written description. 
 

 What is conventional or well known to one of ordinary skill in
 the art need not be disclosed in detail. See Hybritech Inc. v.
 Monoclonal Antibodies, Inc., 802 F.2d at 1384, 231 USPQ at 94. See
 also Capon v. Eshhar, 418 F.3d 1349, 1357, 76 USPQ2d 1078,
 1085 (Fed. Cir. 2005) (“The ‘written description’ requirement must be applied
 in the context of the particular invention and the state of the knowledge…. As
 each field evolves, the balance also evolves between what is known and what is
 added by each inventive contribution.”). If a skilled artisan would have
 understood the inventor to be in possession of the claimed invention at the
 time of filing, even if every nuance of the claims is not explicitly described
 in the specification, then the adequate description requirement is met. See,
 e.g., Vas-Cath, 935 F.2d at 1563, 19 USPQ2d at 1116;
 Martin v. Johnson, 454 F.2d 746, 751, 172 USPQ 391, 395
 (CCPA 1972) (stating “the description need not be in ipsis
 verbis [i.e., “in the same words”] to be sufficient”).
 

 A claim which is limited to a single disclosed embodiment or
 species is analyzed as a claim drawn to a single embodiment or species, whereas
 a claim which encompasses two or more embodiments or species within the scope
 of the claim is analyzed as a claim drawn to a genus. See also
 MPEP §
 806.04(e) .
 

 i) For Each Claim Drawn to a Single Embodiment or Species: 
 (A) Determine whether the application describes an actual
 reduction to practice of the claimed invention.
 

 
 
 (B) If the application does not describe an actual
 reduction to practice, determine whether the invention is complete as
 evidenced by a reduction to drawings or structural chemical formulas
 that are sufficiently detailed to show that inventor was in possession
 of the claimed invention as a whole.
 

 
 
 (C) If the application does not describe an actual
 reduction to practice or reduction to drawings or structural chemical
 formula as discussed above, determine whether the invention has been
 set forth in terms of distinguishing identifying characteristics as
 evidenced by other descriptions of the invention that are sufficiently
 detailed to show that inventor was in possession of the claimed
 invention.
 
 (1) Determine whether the application as filed
 describes the complete structure (or acts of a process) of the
 claimed invention as a whole. The complete structure of a
 species or embodiment typically satisfies the requirement that
 the description be set forth “in such full, clear, concise, and
 exact terms” to show possession of the claimed invention.
 35 U.S.C.
 112(a) or pre-AIA 35
 U.S.C. 112 , first paragraph;
 cf. Fields v. Conover, 443 F.2d 1386, 1392, 170
 USPQ 276, 280 (CCPA 1971) (finding a lack of written description
 because the specification lacked the “full, clear, concise, and
 exact written description” which is necessary to support the
 claimed invention). If a complete structure is disclosed, the
 written description requirement is satisfied for that species or
 embodiment, and a rejection under 35
 U.S.C. 112(a) or pre-AIA 35
 U.S.C. 112 , first paragraph, for lack of
 written description must not be made.
 

 (2) If the application as filed does not disclose
 the complete structure (or acts of a process) of the claimed
 invention as a whole, determine whether the specification
 discloses other relevant identifying characteristics sufficient
 to describe the claimed invention in such full, clear, concise,
 and exact terms that a skilled artisan would recognize inventor
 was in possession of the claimed invention. For example, in the
 biotech art, if a strong correlation has been established
 between structure and function, one skilled in the art would be
 able to predict with a reasonable degree of confidence the
 structure of the claimed invention from a recitation of its
 function. Thus, the written description requirement may be
 satisfied through disclosure of function and minimal structure
 when there is a well-established correlation between structure
 and function. In contrast, without such a correlation, the
 capability to recognize or understand the structure from the
 mere recitation of function and minimal structure is highly
 unlikely. In this latter case, disclosure of function alone is
 little more than a wish for possession; it does not satisfy the
 written description requirement. See Eli
 Lilly, 119 F.3d at 1568, 43 USPQ2d at 1406 (written
 description requirement not satisfied by merely providing “a
 result that one might achieve if one made that invention”);
 In re Wilder, 736 F.2d 1516, 1521, 222
 USPQ 369, 372-73 (Fed. Cir. 1984) (affirming a rejection for
 lack of written description because the specification does
 “little more than outline goals appellants hope the claimed
 invention achieves and the problems the invention will hopefully
 ameliorate”). 
 

 
 

 
 Whether the specification shows that the inventor was in
 possession of the claimed invention is not a single, simple determination,
 but rather is a factual determination reached by considering a number of
 factors. Factors to be considered in determining whether there is sufficient
 evidence of possession include the level of skill and knowledge in the art,
 partial structure, physical and/or chemical properties, functional
 characteristics alone or coupled with a known or disclosed correlation
 between structure and function, and the method of making the claimed
 invention. Disclosure of any combination of such identifying characteristics
 that distinguish the claimed invention from other materials and would lead
 one of skill in the art to the conclusion that the inventor was in
 possession of the claimed species is sufficient. See Eli
 Lilly, 119 F.3d at 1568, 43 USPQ2d at 1406. The description
 needed to satisfy the requirements of 35 U.S.C. 112 “varies
 with the nature and scope of the invention at issue, and with the scientific
 and technologic knowledge already in existence.” Capon v.
 Eshhar, 418 F.3d at 1357, 76 USPQ2d at 1084. Patents and
 printed publications in the art should be relied upon to determine whether
 an art is mature and what the level of knowledge and skill is in the art. In
 most technologies which are mature, and wherein the knowledge and level of
 skill in the art is high, a written description question should not be
 raised for claims present in the application when originally filed, even if
 the specification discloses only a method of making the invention and the
 function of the invention. 
 

 In contrast, for inventions in emerging and unpredictable
 technologies, or for inventions characterized by factors not reasonably
 predictable which are known to one of ordinary skill in the art, more
 evidence is required to show possession. For example, disclosure of only a
 method of making the invention and the function may not be sufficient to
 support a product claim other than a product-by-process claim. See, e.g.,
 Fiers v. Revel, 984 F.2d at 1169, 25 USPQ2d at 1605;
 Amgen, 927 F.2d at 1206, 18 USPQ2d at 1021. Where the
 process has actually been used to produce the product, the written
 description requirement for a product-by-process claim is clearly satisfied;
 however, the requirement may not be satisfied where it is not clear that the
 acts set forth in the specification can be performed, or that the product is
 produced by that process. Furthermore, disclosure of a partial structure
 without additional characterization of the product may not be sufficient to
 evidence possession of the claimed invention. See, e.g.,
 Amgen, 927 F.2d at 1206, 18 USPQ2d at 1021 (“A gene is
 a chemical compound, albeit a complex one, and it is well established in our
 law that conception of a chemical compound requires that the inventor be
 able to define it so as to distinguish it from other materials, and to
 describe how to obtain it. Conception does not occur unless one has a mental
 picture of the structure of the chemical, or is able to define it by its
 method of preparation, its physical or chemical properties, or whatever
 characteristics sufficiently distinguish it. It is not sufficient to define
 it solely by its principal biological property, e.g., encoding human
 erythropoietin, because an alleged conception having no more specificity
 than that is simply a wish to know the identity of any material with that
 biological property. We hold that when an inventor is unable to envision the
 detailed constitution of a gene so as to distinguish it from other
 materials, as well as a method for obtaining it, conception has not been
 achieved until reduction to practice has occurred, i.e., until after the
 gene has been isolated.” (citations omitted)). In such instances the alleged
 conception fails not merely because the field is unpredictable or because of
 the general uncertainty surrounding experimental sciences, but because the
 conception is incomplete due to factual uncertainty that undermines the
 specificity of the inventor’s idea of the invention. Burroughs
 Wellcome Co. v. Barr Labs. Inc., 40 F.3d 1223, 1229, 32 USPQ2d
 1915, 1920 (Fed. Cir. 1994). Reduction to practice in effect provides the
 only evidence to corroborate conception (and therefore possession) of the
 invention. Id. 

 Any claim to a species that does not meet the test
 described under at least one of (a), (b), or (c) must be rejected as lacking
 adequate written description under 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 ,
 first paragraph.
 

 ii) For each claim drawn to a genus: The written description requirement for a claimed genus
 may be satisfied through sufficient description of a representative number
 of species by actual reduction to practice (see i)(A) above), reduction to
 drawings (see i)(B) above), or by disclosure of relevant, identifying
 characteristics, i.e., structure or other physical and/or chemical
 properties, by functional characteristics coupled with a known or disclosed
 correlation between function and structure, or by a combination of such
 identifying characteristics, sufficient to show the inventor was in
 possession of the claimed genus (see i)(C) above). See Eli
 Lilly, 119 F.3d at 1568, 43 USPQ2d at 1406. See Juno
 Therapeutics, Inc. v. Kite Pharma, Inc., 10 F.4th 1330, 1337,
 2021 USPQ2d 893 (Fed. Cir. 2021) ( "[T]he written description must lead a
 person of ordinary skill in the art to understand that the inventor
 possessed the entire scope of the claimed invention.
 Ariad, 598 F.3d at 1353–54 ('[T]he purpose of the
 written description requirement is to ensure that the scope of the right to
 exclude, as set forth in the claims, does not overreach the scope of the
 inventor's contribution to the field of art as described in the patent
 specification.' (internal quotation marks omitted).").
 

 A “representative number of species” means that the
 species which are adequately described are representative of the entire
 genus. Thus, when there is substantial variation within the genus, one must
 describe a sufficient variety of species to reflect the variation within the
 genus. See AbbVie Deutschland GmbH & Co., KG v. Janssen
 Biotech, Inc., 759 F.3d 1285, 1300, 111 USPQ2d 1780, 1790 (Fed.
 Cir. 2014) (Claims directed to a functionally defined genus of antibodies
 were not supported by a disclosure that “only describe[d] one type of
 structurally similar antibodies” that “are not representative of the full
 variety or scope of the genus.”). The disclosure of only one species
 encompassed within a genus adequately describes a claim directed to that
 genus only if the disclosure “indicates that the patentee has invented
 species sufficient to constitute the gen[us].” See Enzo
 Biochem, 323 F.3d at 966, 63 USPQ2d at 1615; Noelle v.
 Lederman, 355 F.3d 1343, 1350, 69 USPQ2d 1508, 1514 (Fed. Cir.
 2004) (Fed. Cir. 2004) (“[A] patentee of a biotechnological invention cannot
 necessarily claim a genus after only describing a limited number of species
 because there may be unpredictability in the results obtained from species
 other than those specifically enumerated.”). “A patentee will not be deemed
 to have invented species sufficient to constitute the genus by virtue of
 having disclosed a single species when … the evidence indicates ordinary
 artisans could not predict the operability in the invention of any species
 other than the one disclosed.” In re Curtis, 354 F.3d
 1347, 1358, 69 USPQ2d 1274, 1282 (Fed. Cir. 2004) (Claims directed to PTFE
 dental floss with a friction-enhancing coating were not supported by a
 disclosure of a microcrystalline wax coating where there was no evidence in
 the disclosure or anywhere else in the record showing applicant conveyed
 that any other coating was suitable for a PTFE dental floss.) On the other
 hand, there may be situations where one species adequately supports a genus.
 See, e.g., Rasmussen, 650 F.2d at 1214, 211 USPQ at
 326-27 (disclosure of a single method of adheringly applying one layer to
 another was sufficient to support a generic claim to “adheringly applying”
 because one skilled in the art reading the specification would understand
 that it is unimportant how the layers are adhered, so long as they are
 adhered); In re Herschler, 591 F.2d 693, 697, 200 USPQ
 711, 714 (CCPA 1979) (disclosure of corticosteroid in DMSO sufficient to
 support claims drawn to a method of using a mixture of a “physiologically
 active steroid” and DMSO because “use of known chemical compounds in a
 manner auxiliary to the invention must have a corresponding written
 description only so specific as to lead one having ordinary skill in the art
 to that class of compounds. Occasionally, a functional recitation of those
 known compounds in the specification may be sufficient as that
 description.”); In re Smythe, 480 F.2d 1376, 1383, 178
 USPQ 279, 285 (CCPA 1973) (the phrase “air or other gas which is inert to
 the liquid” was sufficient to support a claim to “inert fluid media” because
 the description of the properties and functions of the air or other gas
 segmentizing medium would suggest to a person skilled in the art that
 appellant’s invention includes the use of “inert fluid” broadly.). See
 Juno, 10 F.4th 1337, 2021 USPQ2d 893 (Fed. Cir. 2021)
 (where the claims are directed to species that bind to various selected
 targets, it is not fatal that all species are not disclosed as long as the
 patent provides other means of identifying which species would possess the
 claimed common structural characteristics or shared traits). 
 

 The Federal Circuit has explained that a specification
 cannot always support expansive claim language and satisfy the requirements
 of 35
 U.S.C. 112 “merely by clearly describing one
 embodiment of the thing claimed.” LizardTech v. Earth Resource
 Mapping, Inc., 424 F.3d 1336, 1346, 76 USPQ2d 1731, 1733 (Fed.
 Cir. 2005). The issue is whether a person skilled in the art would
 understand inventor to have invented, and been in possession of, the
 invention as broadly claimed. In LizardTech, claims to a
 generic method of making a seamless discrete wavelet transformation (DWT)
 were held invalid under 35 U.S.C. 112 , first
 paragraph, because the specification taught only one particular method for
 making a seamless DWT and there was no evidence that the specification
 contemplated a more generic method. Id. ; see also
 Tronzo v. Biomet, 156 F.3d at 1159, 47 USPQ2d at 1833
 (Fed. Cir. 1998)(holding that the disclosure of a species in a parent
 application did not provide adequate written description support for claims
 to a genus in a child application where the specification taught against
 other species). 
 

 Satisfactory disclosure of a “representative number”
 depends on whether one of skill in the art would recognize that the inventor
 was in possession of the necessary common attributes or features possessed
 by the members of the genus in view of the species disclosed. For inventions
 in an unpredictable art, adequate written description of a genus which
 embraces widely variant species cannot be achieved by disclosing only one
 species within the genus. See, e.g., Eli Lilly, 119 F.3d
 at 1568, 43 USPQ2d at 1406. Instead, the disclosure must adequately reflect
 the structural diversity of the claimed genus, either through the disclosure
 of sufficient species that are “representative of the full variety or scope
 of the genus,” or by the establishment of “a reasonable structure-function
 correlation.” Such correlations may be established “by the inventor as
 described in the specification,” or they may be “known in the art at the
 time of the filing date.” See AbbVie, 759 F.3d at
 1300-01, 111 USPQ2d 1780, 1790-91 (Fed. Cir. 2014) (Holding that claims to
 all human antibodies that bind IL-12 with a particular binding affinity rate
 constant (i.e., k off ) were not adequately supported
 by a specification describing only a single type of human antibody having
 the claimed features because the disclosed antibody was not representative
 of other types of antibodies in the claimed genus, as demonstrated by the
 fact that other disclosed antibodies had different types of heavy and light
 chains, and shared only a 50% sequence similarity in their variable regions
 with the disclosed antibodies.). Description of a representative number of
 species does not require the description to be of such specificity that it
 would provide individual support for each species that the genus embraces.
 For example, in the molecular biology arts, if an applicant disclosed an
 amino acid sequence, it would be unnecessary to provide an explicit
 disclosure of nucleic acid sequences that encoded the amino acid sequence.
 Since the genetic code is widely known, a disclosure of an amino acid
 sequence would provide sufficient information such that one would accept
 that an inventor was in possession of the full genus of nucleic acids
 encoding a given amino acid sequence, but not necessarily any particular
 species. Cf. In re Bell, 991 F.2d 781, 785, 26 USPQ2d
 1529, 1532 (Fed. Cir. 1993) and In re Baird, 16 F.3d 380,
 382, 29 USPQ2d 1550, 1552 (Fed. Cir. 1994). If a representative number of
 adequately described species are not disclosed for a genus, the claim to
 that genus must be rejected as lacking adequate written description under
 35 U.S.C. 112(a) or
 pre-AIA
 35 U.S.C. 112 , first paragraph.
 

 (b) New Claims, Amended Claims, or Claims Asserting Entitlement to the
 Benefit of an Earlier Priority Date or Filing Date under 35 U.S.C. 119, 120,
 365, or 386 The examiner has the initial burden of presenting evidence or
 reasoning to explain why persons skilled in the art would not recognize in the
 original disclosure a description of the invention defined by the claims. See
 Wertheim, 541 F.2d at 263, 191 USPQ at 97 (“[T]he PTO has
 the initial burden of presenting evidence or reasons why persons skilled in the
 art would not recognize in the disclosure a description of the invention
 defined by the claims.”). However, when filing an amendment an applicant should
 show support in the original disclosure for new or amended claims. See
 MPEP §§
 714.02 and 2163.06 (“Applicant should ...
 specifically point out the support for any amendments made to the
 disclosure.”). 
 

 To comply with the written description requirement of
 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 ,
 first paragraph, or to be entitled to an earlier priority date or filing date
 under 35
 U.S.C. 119 , 120 , 365 , or
 386 , each claim limitation must be expressly,
 implicitly, or inherently supported in the originally filed disclosure. When an
 explicit limitation in a claim “is not present in the written description whose
 benefit is sought it must be shown that a person of ordinary skill would have
 understood, at the time the patent application was filed, that the description
 requires that limitation.” Hyatt v. Boone, 146 F.3d 1348,
 1353, 47 USPQ2d 1128, 1131 (Fed. Cir. 1998); see also Akeva LLC v.
 Nike, Inc., 817 Fed. Appx. 1005, 1012-13, 2020 USPQ2d 10797 (Fed.
 Cir. 2020) (The court found that the continuation patents were not entitled to
 the benefit of an earlier filing date because the continuation patents removed
 a disclaimer that the invention did not cover shoes with conventional fixed
 rear soles that was present in the earlier filed patents); In re
 Wright, 866 F.2d 422, 425, 9 USPQ2d 1649, 1651 (Fed. Cir. 1989)
 (Original specification for method of forming images using photosensitive
 microcapsules which describes removal of microcapsules from surface and warns
 that capsules not be disturbed prior to formation of image, unequivocally
 teaches absence of permanently fixed microcapsules and supports amended
 language of claims requiring that microcapsules be “not permanently fixed” to
 underlying surface, and therefore meets description requirement of
 35 U.S.C.
 112 .); In re Robins, 429 F.2d 452,
 456-57, 166 USPQ 552, 555 (CCPA 1970) (“[W]here no explicit description of a
 generic invention is to be found in the specification[,] ... mention of
 representative compounds may provide an implicit description upon which to base
 generic claim language.”); In re Smith, 458 F.2d 1389, 1395,
 173 USPQ 679, 683 (CCPA 1972) (a subgenus is not necessarily implicitly
 described by a genus encompassing it and a species upon which it reads);
 Regents of the Univ. of Minnesota v. Gilead Scis., Inc., 
 61 F.4th 1350, 1356-58, 2023 USPQ2d 269 (Fed. Cir. 2023) ( The court found the
 later-filed patent claims could not receive benefit under 35 U.S.C.
 120 , because the earlier-filed applications did not have
 ipsis verbis disclosure of the claimed subgenus and did not provide sufficient
 blaze marks to provide the later-filed claims with sufficient support under
 35 U.S.C. 112(a) .) ; In re Robertson, 
 169 F.3d 743, 745, 49 USPQ2d 1949, 1950-51 (Fed. Cir. 1999) (“To establish
 inherency, the extrinsic evidence ‘must make clear that the missing descriptive
 matter is necessarily present in the thing described in the reference, and that
 it would be so recognized by persons of ordinary skill. Inherency, however, may
 not be established by probabilities or possibilities. The mere fact that a
 certain thing may result from a given set of circumstances is not sufficient.’”
 (citations omitted)); Yeda Research and Dev. Co. v. Abbott GMBH &
 Co., 837 F.3d 1341, 120 USPQ2d 1299 (Fed. Cir. 2016) (“Under the
 doctrine of inherent disclosure, when a specification describes an invention
 that has certain undisclosed yet inherent properties, that specification serves
 as adequate written description to support a subsequent patent application that
 explicitly recites the invention’s inherent properties.”) (citing
 Kennecott Corp. v. Kyocera Int’l, Inc., 835 F.2d 1419,
 1423, 5 USPQ2d 1194 (Fed. Cir. 1987)). Furthermore, each claim must include all
 elements which applicant has described as essential. See, e.g.,
 Johnson Worldwide Assoc. Inc. v. Zebco Corp., 175 F.3d at
 993, 50 USPQ2d at 1613; Gentry Gallery, Inc. v. Berkline
 Corp., 134 F.3d at 1479, 45 USPQ2d at 1503; Tronzo v.
 Biomet, 156 F.3d at 1159, 47 USPQ2d at 1833.
 

 If the originally filed disclosure does not provide support
 for each claim limitation, or if an element which applicant describes as
 essential or critical is not claimed, a new or amended claim must be rejected
 under 35 U.S.C. 112(a) or
 pre-AIA 35
 U.S.C. 112 , first paragraph, as lacking adequate written
 description, or in the case of a priority or benefit claim under
 35 U.S.C.
 119 , 120 , 365 , or
 386 , the priority or benefit claim must be denied.
 

 III. COMPLETE PATENTABILITY DETERMINATION UNDER ALL STATUTORY REQUIREMENTS AND CLEARLY
 COMMUNICATE FINDINGS, CONCLUSIONS, AND THEIR BASES The above only describes how to determine whether the written
 description requirement of 35 U.S.C. 112(a) or
 pre-AIA 35 U.S.C.
 112 , first paragraph, is satisfied. Regardless of the outcome of
 that determination, Office personnel must complete the patentability determination under
 all the relevant statutory provisions of title 35 of the U.S. Code.
 

 Once Office personnel have concluded analysis of the claimed invention
 under all the statutory provisions, including 35 U.S.C. 101 , 112 ,
 102 , and 103 , they should review all the
 proposed rejections and their bases to confirm their correctness. Only then should any
 rejection be imposed in an Office action. The Office action should clearly communicate
 the findings, conclusions, and reasons which support them. When possible, the Office
 action should offer helpful suggestions on how to overcome rejections.
 

 A. For Each Claim Lacking Written Description Support, Reject the Claim
 Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, first paragraph, for Lack of
 Adequate Written Description A description as filed is presumed to be adequate, unless or until
 sufficient evidence or reasoning to the contrary has been presented by the examiner
 to rebut the presumption. See, e.g., In re Marzocchi, 439 F.2d
 220, 224, 169 USPQ 367, 370 (CCPA 1971). The examiner, therefore, must have a
 reasonable basis to challenge the adequacy of the written description. The examiner
 has the initial burden of presenting by a preponderance of evidence why a person
 skilled in the art would not recognize in an applicant’s disclosure a description of
 the invention defined by the claims. Wertheim, 541 F.2d at 263,
 191 USPQ at 97. In rejecting a claim, the examiner must set forth express findings of
 fact regarding the above analysis which support the lack of written description
 conclusion. These findings should:
 

 
 (A) Identify the claim limitation at issue; and

 (B) Establish a prima facie case by providing
 reasons why a person skilled in the art at the time the application was filed
 would not have recognized that the inventor was in possession of the invention
 as claimed in view of the disclosure of the application as filed. A general
 allegation of “unpredictability in the art” is not a sufficient reason to
 support a rejection for lack of adequate written description.
 

 
 When appropriate, suggest amendments to the claims which can be
 supported by the application’s written description, being mindful of the prohibition
 against the addition of new matter in the claims or description. See
 Rasmussen, 650 F.2d at 1214, 211 USPQ at 326.
 

 B. Upon Reply by Applicant, Again Determine the Patentability of the Claimed
 Invention, Including Whether the Written Description Requirement Is Satisfied
 by Reperforming the Analysis Described Above in View of the Whole
 Record Upon reply by applicant, before repeating any rejection under
 35
 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, for lack of written description, review the basis for the rejection in
 view of the record as a whole, including amendments, arguments, and any evidence
 submitted by applicant. If the whole record now demonstrates that the written
 description requirement is satisfied, do not repeat the rejection in the next Office
 action. If the record still does not demonstrate that the written description is
 adequate to support the claim(s), repeat the rejection under 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, fully respond to applicant’s rebuttal arguments, and properly treat any
 further showings submitted by applicant in the reply. When a rejection is maintained,
 any affidavits relevant to the 35 U.S.C. 112(a) or
 pre-AIA 35
 U.S.C. 112 , first paragraph, written description requirement,
 must be thoroughly analyzed and discussed in the next Office action. See In
 re Alton, 76 F.3d 1168, 1176, 37 USPQ2d 1578, 1584 (Fed. Cir. 1996).
 

 
 2163.01 Support for the Claimed Subject Matter in
 Disclosure [R-11.2013]
 

 A written description requirement issue generally involves the question
 of whether the subject matter of a claim is supported by [conforms to] the disclosure of
 an application as filed. If the examiner concludes that the claimed subject matter is
 not supported [described] in an application as filed, this would result in a rejection
 of the claim on the ground of a lack of written description under 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, or denial of the benefit of the filing date of a previously filed
 application. The claim should not be rejected or objected to on the ground of new
 matter. As framed by the court in In re Rasmussen, 650 F.2d 1212, 211
 USPQ 323 (CCPA 1981), the concept of new matter is properly employed as a basis for
 objection to amendments to the abstract, specification or drawings attempting to add new
 disclosure to that originally presented. While the test or analysis of description
 requirement and new matter issues is the same, the examining procedure and statutory
 basis for addressing these issues differ. See MPEP § 2163.06 .
 

 

 
 2163.02 Standard for Determining Compliance With the Written
 Description Requirement [R-07.2022]
 

 The courts have described the essential question to be addressed in a
 description requirement issue in a variety of ways. An objective standard for
 determining compliance with the written description requirement is, “does the
 description clearly allow persons of ordinary skill in the art to recognize that he or
 she invented what is claimed.” In re Gosteli, 872 F.2d 1008, 1012, 10 USPQ2d 1614, 1618 (Fed. Cir. 1989).
 Under Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1563-64, 19 USPQ2d 1111, 1117 (Fed. Cir.
 1991), to satisfy the written description requirement, an applicant must convey with
 reasonable clarity to those skilled in the art that, as of the filing date sought, the
 inventor was in possession of the invention, and that the invention, in that context, is
 whatever is now claimed. The test for sufficiency of support in a parent application is
 whether the disclosure of the application relied upon “reasonably conveys to the artisan
 that the inventor had possession at that time of the later claimed subject matter.”
 Ralston Purina Co. v. Far-Mar-Co., Inc., 772 F.2d 1570, 1575, 227 USPQ 177, 179 (Fed. Cir.
 1985) (quoting In re Kaslow, 707 F.2d 1366, 1375, 217 USPQ 1089, 1096 (Fed. Cir.
 1983)).
 

 Whenever the issue arises, the fundamental factual inquiry is whether
 the specification conveys with reasonable clarity to those skilled in the art that, as
 of the filing date sought, inventor was in possession of the invention as now claimed.
 See, e.g., Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1563-64, 19
 USPQ2d 1111, 1117 (Fed. Cir. 1991). An applicant shows that the inventor was in
 possession of the claimed invention by describing the claimed invention with all of its
 limitations using such descriptive means as words, structures, figures, diagrams, and
 formulas that fully set forth the claimed invention. Lockwood v. Am. Airlines,
 Inc., 107 F.3d 1565, 1572, 41 USPQ2d 1961, 1966 (Fed. Cir. 1997).
 Possession may be shown in a variety of ways including description of an actual
 reduction to practice, or by showing that the invention was “ready for patenting” such
 as by the disclosure of drawings or structural chemical formulas that show that the
 invention was complete, or by describing distinguishing identifying characteristics
 sufficient to show that the inventor was in possession of the claimed invention. See,
 e.g., Pfaff v. Wells Elecs., Inc., 525 U.S. 55, 68, 119 S.Ct. 304,
 312, 48 USPQ2d 1641, 1647 (1998); Regents of the Univ. of Cal. v. Eli
 Lilly, 119 F.3d 1559, 1568, 43 USPQ2d 1398, 1406 (Fed. Cir. 1997);
 Amgen, Inc. v. Chugai Pharm., 927 F.2d 1200, 1206, 18 USPQ2d 1016,
 1021 (Fed. Cir. 1991) (one must define a compound by “whatever characteristics
 sufficiently distinguish it”).
 

 The subject matter of the claim need not be described literally (i.e.,
 using the same terms or in haec verba ) in order for the disclosure to
 satisfy the description requirement. If a claim is amended to include subject matter,
 limitations, or terminology not present in the application as filed, involving a
 departure from, addition to, or deletion from the disclosure of the application as
 filed, the examiner should conclude that the claimed subject matter is not described in
 that application. This conclusion will result in the rejection of the claims affected
 under 35
 U.S.C. 112(a) or pre-AIA 35 U.S.C.112 , first
 paragraph - description requirement, or denial of the benefit of the filing date of a
 previously filed application, as appropriate.
 

 See MPEP
 § 2163 for examination guidelines pertaining to the written
 description requirement.
 

 

 
 2163.03 Typical Circumstances Where Adequate Written Description Issue
 Arises [R-01.2024]
 

 A description requirement issue can arise in a number of different
 circumstances where it must be determined whether the subject matter of a claim is
 supported in an application as filed. See MPEP § 2163 for examination guidelines
 pertaining to the written description requirement. Most typically, the issue will arise
 in the following circumstances: 
 

 I. AMENDMENT AFFECTING A CLAIM An amendment to the claims or the addition of a new claim must be
 supported by the description of the invention in the application as filed.
 In re Wright, 866 F.2d 422, 9 USPQ2d 1649 (Fed. Cir. 1989). An amendment
 to the specification (e.g., a change in the definition of a term used both in the
 specification and claim) may indirectly affect a claim even though no actual
 amendment is made to the claim. 
 

 II. RELIANCE ON FILING DATE OF PARENT APPLICATION UNDER 35 U.S.C. 120 Under 35 U.S.C. 120 , the claims in a
 U.S. application are entitled to the benefit of the filing date of an earlier filed
 U.S. application if the subject matter of the claim is disclosed in the manner
 provided by 35 U.S.C. 112(a) or
 pre-AIA
 35 U.S.C. 112 , first paragraph in the earlier filed
 application. See, e.g., Tronzo v. Biomet, Inc., 156 F.3d 1154, 47
 USPQ2d 1829 (Fed. Cir. 1998); In re Scheiber, 587 F.2d 59, 199 USPQ 782 (CCPA 1978). See also
 Regents of the Univ. of Minnesota v. Gilead Scis., Inc., 61
 F.4th 1350, 2023 USPQ2d 269 (Fed. Cir. 2023). The court noted that the Board
 evaluated whether the earlier- filed applications provided an “ ipsis
 verbis ” disclosure of the claimed subgenus. In reviewing this
 evaluation, the court agreed with the Board that the earlier-filed applications
 recited a compendium of common organic chemical functional groups, yielding a laundry
 list disclosure of different moieties for every possible side chain or functional
 group. Id. at 1357. Thus, it was unclear how many compounds
 actually fell within the described genera and subgenera. Id. The
 court also noted that the Board then evaluated whether the prior applications
 “provided sufficient blaze marks to provide written description support for the ‘830
 patent claims.” Id. at 1357. The court agreed with the Board that
 there were no adequate blaze marks. Id. at 1358. Therefore, the
 court held that the earlier-filed applications did not provide sufficient written
 description to support the later-filed patent claims under 35 U.S.C.
 120 .
 

 III. RELIANCE ON PRIORITY UNDER 35 U.S.C. 119 Under 35 U.S.C. 119(a) or (e) , the
 claims in a U.S. application are entitled to the benefit of a foreign priority date
 or the filing date of a provisional application if the corresponding foreign
 application or provisional application supports the claims in the manner required by
 35
 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph. Purdue Pharma LP v. Iancu, 767 Fed. Appx. 918, 923-24,
 2019 USPQ2d 136363 (Fed. Cir. 2019); In re Ziegler, 992 F.2d 1197, 1200, 26 USPQ2d 1600, 1603 (Fed. Cir.
 1993); Kawai v. Metlesics, 480 F.2d 880, 178 USPQ 158 (CCPA 1973); In
 re Gosteli, 872 F.2d 1008, 10 USPQ2d 1614 (Fed. Cir. 1989).
 

 IV. SUPPORT FOR A CLAIM CORRESPONDING TO A COUNT IN AN INTERFERENCE In an interference proceeding, the claim corresponding to a count
 must be supported by the specification in the manner provided by 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph. Fields v. Conover, 443 F.2d 1386, 170 USPQ 276 (CCPA
 1971) (A broad generic disclosure to a class of compounds was not a sufficient
 written description of a specific compound within the class.). Furthermore, when a
 party to an interference seeks the benefit of an earlier-filed U.S. patent
 application, the earlier application must meet the requirements of 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph for the subject matter of the count. Hyatt v. Boone, 146
 F.3d 1348, 1352, 47 USPQ2d 1128, 1130 (Fed. Cir. 1998).
 

 V. ORIGINAL CLAIM NOT SUFFICIENTLY
 DESCRIBED While there is a presumption that an adequate written
 description of the claimed invention is present in the specification as filed.
 In re Wertheim, 541 F.2d 257, 262, 191 USPQ 90, 96 (CCPA 1976),
 a question as to whether a specification provides an adequate written description may
 arise in the context of an original claim. An original claim may lack written
 description support when (1) the claim defines the invention in functional language
 specifying a desired result but the disclosure fails to sufficiently identify how the
 function is performed or the result is achieved or (2) a broad genus claim is
 presented but the disclosure only describes a narrow species with no evidence that
 the genus is contemplated. See Ariad Pharms., Inc. v. Eli Lilly &
 Co., 598 F.3d 1336, 1349-50 (Fed. Cir. 2010) ( en
 banc ). The written description requirement is not necessarily met when the
 claim language appears in ipsis verbis in the specification. “Even
 if a claim is supported by the specification, the language of the specification, to
 the extent possible, must describe the claimed invention so that one skilled in the
 art can recognize what is claimed. The appearance of mere indistinct words in a
 specification or a claim, even an original claim, does not necessarily satisfy that
 requirement.” Enzo Biochem, Inc. v. Gen-Probe, Inc., 323 F.3d
 956, 968, 63 USPQ2d 1609, 1616 (Fed. Cir. 2002).
 

 See MPEP § 2163 , subsection I.A and
 MPEP §
 2163 , subsection II.A.3(a) for further discussion of
 rebutting the presumption of adequate written description for originally presented
 claims. 
 

 VI. INDEFINITENESS REJECTION OF A MEANS- (OR STEP-) PLUS-FUNCTION
 LIMITATION A claim limitation expressed in means- (or step-)
 plus-function language “shall be construed to cover the corresponding structure,
 material, or acts described in the specification and equivalents thereof.”
 35
 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112 , sixth
 paragraph. If the specification fails to disclose sufficient corresponding structure,
 materials, or acts that perform the entire claimed function, then the claim
 limitation is indefinite because the applicant has in effect failed to particularly
 point out and distinctly claim the invention as required by 35 U.S.C.
 112(b) or pre-AIA 35 U.S.C. 112 , second
 paragraph. In re Donaldson Co., 16 F.3d 1189, 1195, 29 USPQ2d
 1845, 1850 (Fed. Cir. 1994) ( en banc ). Such a limitation also
 lacks an adequate written description as required by 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, because an indefinite, unbounded functional limitation would cover all
 ways of performing a function and indicate that the inventor has not provided
 sufficient disclosure to show possession of the invention. See also
 MPEP §
 2181 .
 

 

 
 2163.04 Burden on the Examiner with Regard to the Written Description
 Requirement [R-11.2013]
 

 The inquiry into whether the description requirement is met must be
 determined on a case-by-case basis and is a question of fact. In re Wertheim, 541 F.2d 257, 262, 191 USPQ 90, 96 (CCPA 1976). A
 description as filed is presumed to be adequate, unless or until sufficient evidence or
 reasoning to the contrary has been presented by the examiner to rebut the presumption.
 See, e.g., In re Marzocchi, 439 F.2d 220, 224, 169 USPQ 367, 370
 (CCPA 1971). The examiner, therefore, must have a reasonable basis to challenge the
 adequacy of the written description. The examiner has the initial burden of presenting
 by a preponderance of evidence why a person skilled in the art would not recognize in an
 applicant’s disclosure a description of the invention defined by the claims.
 Wertheim, 541 F.2d at 263, 191 USPQ at 97. 
 

 I. STATEMENT OF REJECTION REQUIREMENTS In rejecting a claim, the examiner must set forth express findings
 of fact which support the lack of written description conclusion (see
 MPEP §
 2163 for examination guidelines pertaining to the written
 description requirement). These findings should:
 

 
 (A) Identify the claim limitation(s) at issue; and

 (B) Establish a prima facie case by providing
 reasons why a person skilled in the art at the time the application was filed
 would not have recognized that the inventor was in possession of the invention
 as claimed in view of the disclosure of the application as filed. A general
 allegation of “unpredictability in the art” is not a sufficient reason to
 support a rejection for lack of adequate written description. A simple
 statement such as “Applicant has not pointed out where the new (or amended)
 claim is supported, nor does there appear to be a written description of the
 claim limitation ‘____’ in the application as filed.” may be sufficient where
 the claim is a new or amended claim, the support for the limitation is not
 apparent, and applicant has not pointed out where the limitation is
 supported.
 
 

 

 See Hyatt v. Dudas, 492 F.3d 1365, 1370, 83
 USPQ2d 1373, 1376 (Fed. Cir. 2007) (holding that “ [MPEP] §
 2163.04 [subsection] (I)(B) as written is a lawful
 formulation of the prima facie standard for a lack of
 written description rejection.”).
 

 

 
 When appropriate, suggest amendments to the claims which can be
 supported by the application’s written description, being mindful of the prohibition
 against the addition of new matter in the claims or description. See
 Rasmussen, 650 F.2d at 1214, 211 USPQ at 326.
 

 II. RESPONSE TO APPLICANT’S REPLY Upon reply by applicant, before repeating any rejection under
 35
 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, for lack of written description, review the basis for the rejection in
 view of the record as a whole, including amendments, arguments, and any evidence
 submitted by applicant. If the whole record now demonstrates that the written
 description requirement is satisfied, do not repeat the rejection in the next Office
 action. If the record still does not demonstrate that the written description is
 adequate to support the claim(s), repeat the rejection under 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, fully respond to applicant’s rebuttal arguments, and properly treat any
 further showings submitted by applicant in the reply. When a rejection is maintained,
 any affidavits relevant to the 35 U.S.C. 112(a) or
 pre-AIA 35
 U.S.C. 112 , first paragraph, written description requirement,
 must be thoroughly analyzed and discussed in the next Office action. See In
 re Alton, 76 F.3d 1168, 1176, 37 USPQ2d 1578, 1584 (Fed. Cir. 1996).
 

 

 
 2163.05 Changes to the Scope of Claims [R-01.2024]

 The failure to meet the written description requirement of
 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, commonly arises when the claims are changed after filing to either broaden or
 narrow the breadth of the claim limitations, or to alter a numerical range limitation or
 to use claim language which is not synonymous with the terminology used in the original
 disclosure. To comply with the written description requirement of 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, or to be entitled to an earlier priority date or filing date under
 35 U.S.C.
 119 , 120 , or 365(c) , each claim
 limitation must be expressly, implicitly, or inherently supported in the originally
 filed disclosure. See MPEP § 2163 for examination guidelines pertaining to the
 written description requirement.
 

 I. BROADENING CLAIM 
 

 A. Omission of a Limitation Under certain circumstances, omission of a limitation can raise
 an issue regarding whether the inventor had possession of a broader, more generic
 invention. See, e.g., Gentry Gallery, Inc. v. Berkline Corp., 
 134 F.3d 1473, 45 USPQ2d 1498 (Fed. Cir. 1998) (claims to a sectional sofa
 comprising, inter alia, a console and a control means were held
 invalid for failing to satisfy the written description requirement where the
 claims were broadened by removing the location of the control means.);
 Johnson Worldwide Assoc. v. Zebco Corp., 175 F.3d 985, 993,
 50 USPQ2d 1607, 1613 (Fed. Cir. 1999) (In Gentry Gallery, the
 “court’s determination that the patent disclosure did not support a broad meaning
 for the disputed claim terms was premised on clear statements in the written
 description that described the location of a claim element--the ‘control
 means’--as ‘the only possible location’ and that variations were ‘outside the
 stated purpose of the invention.’ Gentry Gallery, 134 F.3d at
 1479, 45 USPQ2d at 1503. Gentry Gallery, then, considers the
 situation where the patent’s disclosure makes crystal clear that a particular
 (i.e., narrow) understanding of a claim term is an ‘essential element of [the
 inventor’s] invention.’”); Tronzo v. Biomet , 156 F.3d at 1158-59, 47 USPQ2d
 at 1833 (Fed. Cir. 1998) (claims to generic cup shape were not entitled to filing
 date of parent application which disclosed “conical cup” in view of the disclosure
 of the parent application stating the advantages and importance of the conical
 shape.); In re Wilder, 736 F.2d 1516, 222 USPQ 369 (Fed. Cir.
 1984) (reissue claim omitting “in synchronism” limitation with respect to scanning
 means and indexing means was not supported by the original patent’s disclosure in
 such a way as to indicate possession, as of the original filing date, of that
 generic invention.). 
 

 A claim that omits an element which applicant describes as an
 essential or critical feature of the invention originally disclosed does not
 comply with the written description requirement. See Gentry
 Gallery, 134 F.3d at 1480, 45 USPQ2d at 1503; In re
 Sus, 306 F.2d 494, 504, 134 USPQ 301, 309 (CCPA 1962) (“[O]ne skilled
 in this art would not be taught by the written description of the invention in the
 specification that any ‘aryl or substituted aryl radical’ would be suitable for
 the purposes of the invention but rather that only certain aryl radicals and
 certain specifically substituted aryl radicals [i.e., aryl azides] would be
 suitable for such purposes.”) (emphasis in original). Compare In re
 Peters, 723 F.2d 891, 221 USPQ 952 (Fed. Cir. 1983) (In a reissue
 application, a claim to a display device was broadened by removing the limitations
 directed to the specific tapered shape of the tips without violating the written
 description requirement. The shape limitation was considered to be unnecessary
 since the specification, as filed, did not describe the tapered shape as essential
 or critical to the operation or patentability of the claim.). A claim which omits
 matter disclosed to be essential to the invention as described in the
 specification or in other statements of record may also be subject to rejection
 under 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, as not enabling, or under 35 U.S.C. 112(b) or
 pre-AIA
 35 U.S.C. 112 , second paragraph. See In re
 Mayhew, 527 F.2d 1229, 188 USPQ 356 (CCPA 1976); In re
 Venezia, 530 F.2d 956, 189 USPQ 149 (CCPA 1976); and In re
 Collier, 397 F.2d 1003, 158 USPQ 266 (CCPA 1968). See also
 MPEP §
 2172.01 .
 

 B. Addition of Generic Claim The written description requirement for a claimed genus may be
 satisfied through sufficient description of a representative number of species. A
 “representative number of species” means that the species which are adequately
 described are representative of the entire genus. Thus, when there is substantial
 variation within the genus, one must describe a sufficient variety of species to
 reflect the variation within the genus. See AbbVie Deutschland GmbH &
 Co., KG v. Janssen Biotech, Inc., 759 F.3d 1285, 1300, 111 USPQ2d
 1780, 1790 (Fed. Cir. 2014) (Claims directed to a functionally defined genus of
 antibodies were not supported by a disclosure that “only describe[d] one type of
 structurally similar antibodies” that “are not representative of the full variety
 or scope of the genus.”). The disclosure of only one species encompassed within a
 genus adequately describes a claim directed to that genus only if the disclosure
 “indicates that the patentee has invented species sufficient to constitute the
 gen[us].” See Enzo Biochem, 323 F.3d at 966, 63 USPQ2d at 1615.
 “A patentee will not be deemed to have invented species sufficient to constitute
 the genus by virtue of having disclosed a single species when … the evidence
 indicates ordinary artisans could not predict the operability in the invention of
 any species other than the one disclosed.” In re Curtis, 354
 F.3d 1347, 1358, 69 USPQ2d 1274, 1282 (Fed. Cir. 2004) (Claims directed to PTFE
 dental floss with a friction-enhancing coating were not supported by a disclosure
 of a microcrystalline wax coating where there was no evidence in the disclosure or
 anywhere else in the record showing applicant conveyed that any other coating was
 suitable for a PTFE dental floss.) On the other hand, there may be situations
 where one species adequately supports a genus. See, e.g., In re
 Rasmussen, 650 F.2d 1212, 1214, 211 USPQ 323, 326-27 (CCPA 1981)
 (disclosure of a single method of adheringly applying one layer to another was
 sufficient to support a generic claim to “adheringly applying” because one skilled
 in the art reading the specification would understand that it is unimportant how
 the layers are adhered, so long as they are adhered); In re
 Herschler, 591 F.2d 693, 697, 200 USPQ 711, 714 (CCPA 1979)
 (disclosure of corticosteriod in DMSO sufficient to support claims drawn to a
 method of using a mixture of a “physiologically active steroid” and DMSO because
 “use of known chemical compounds in a manner auxiliary to the invention must have
 a corresponding written description only so specific as to lead one having
 ordinary skill in the art to that class of compounds. Occasionally, a functional
 recitation of those known compounds in the specification may be sufficient as that
 description.”); In re Smythe, 480 F.2d 1376, 1383, 178 USPQ
 279, 285 (CCPA 1973) (the phrase “air or other gas which is inert to the liquid”
 was sufficient to support a claim to “inert fluid media” because the description
 of the properties and functions of the air or other gas segmentizing medium would
 suggest to a person skilled in the art that appellant’s invention includes the use
 of “inert fluid” broadly.). However, in Tronzo v. Biomet, 156
 F.3d 1154, 1159, 47 USPQ2d 1829, 1833 (Fed. Cir. 1998), the disclosure of a
 species in the parent application did not suffice to provide written description
 support for the genus in the child application where the specification taught
 against other species. See also In re Gosteli, 872 F.2d 1008,
 10 USPQ2d 1614 (Fed. Cir. 1989) (generic and subgeneric claims in the U.S.
 application were not entitled to the benefit of foreign priority where the foreign
 application disclosed only two of the species encompassed by the broad generic
 claim and the subgeneric Markush claim that encompassed 21 compounds). 
 

 II. NARROWING OR SUBGENERIC CLAIM The introduction of claim changes which involve narrowing the claims
 by introducing elements or limitations which are not supported by the as-filed
 disclosure is a violation of the written description requirement of 35 U.S.C.
 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph. See, e.g., Fujikawa v. Wattanasin, 93 F.3d 1559, 1571,
 39 USPQ2d 1895, 1905 (Fed. Cir. 1996) (a “laundry list” disclosure of every possible
 moiety for every possible position does not constitute a written description of every
 species in a genus because it would not “reasonably lead” those skilled in the art to
 any particular species); and Regents of the Univ. of Minnesota v. Gilead
 Scis., Inc., 61 F.4th 1350, 1356-58, 2023 USQ2d 269 (Fed. Cir. 2023). 
 

 In re Ruschig, 379 F.2d 990, 995, 154 USPQ 118, 123 (CCPA 1967)
 (“ If n-propylamine had been used in making the compound instead
 of n-butylamine, the compound of claim 13 would have resulted. Appellants submit to
 us, as they did to the board, an imaginary specific example patterned on specific
 example 6 by which the above butyl compound is made so that we can see what a simple
 change would have resulted in a specific supporting disclosure being present in the
 present specification. The trouble is that there is no such disclosure, easy though
 it is to imagine it.”) (emphasis in original); In Ex parte Ohshiro, 14 USPQ2d 1750 (Bd. Pat. App. & Inter. 1989), the
 Board affirmed the rejection under 35 U.S.C. 112 , first paragraph,
 of claims to an internal combustion engine which recited “at least one of said piston
 and said cylinder (head) having a recessed channel.” The Board held that the
 application which disclosed a cylinder head with a recessed channel and a piston
 without a recessed channel did not specifically disclose the “species” of a channeled
 piston.
 

 While these and other cases find that recitation of an undisclosed
 species may violate the description requirement, a change involving subgeneric
 terminology may or may not be acceptable. Applicant was not entitled to the benefit
 of a parent filing date when the claim was directed to a subgenus (a specified range
 of molecular weight ratios) where the parent application contained a generic
 disclosure and a specific example that fell within the recited range because the
 court held that subgenus range was not described in the parent application.
 In re Lukach, 442 F.2d 967, 169 USPQ 795 (CCPA 1971). On the other hand,
 in Ex parte Sorenson, 3 USPQ2d 1462 (Bd. Pat. App. & Inter. 1987), the
 subgeneric language of “aliphatic carboxylic acid” and “aryl carboxylic acid” did not
 violate the written description requirement because species falling within each
 subgenus were disclosed as well as the generic carboxylic acid. See also In
 re Smith, 458 F.2d 1389, 1395, 173 USPQ 679, 683 (CCPA 1972)
 (“Whatever may be the viability of an inductive-deductive approach to arriving at a
 claimed subgenus, it cannot be said that such a subgenus is
 necessarily described by a genus encompassing it and a species upon which it reads.”
 (emphasis added)). Each case must be decided on its own facts in terms of what is
 reasonably communicated to those skilled in the art. In re Wilder, 736 F.2d 1516, 1520, 222 USPQ 369, 372 (Fed. Cir. 1984).
 
 

 III. RANGE LIMITATIONS With respect to changing numerical range limitations, the analysis
 must take into account which ranges one skilled in the art would consider inherently
 supported by the discussion in the original disclosure. In the decision in
 In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976), the ranges
 described in the original specification included a range of “25%- 60%” and specific
 examples of “36%” and “50%.” A corresponding new claim limitation to “at least 35%”
 did not meet the description requirement because the phrase “at least” had no upper
 limit and caused the claim to read literally on embodiments outside the “25% to 60%”
 range, however a limitation to “between 35% and 60%” did meet the description
 requirement.
 

 See also Purdue Pharma L.P. v. Faulding Inc., 
 230 F.3d 1320, 1328, 56 USPQ2d 1481, 1487 (Fed. Cir. 2000) (“[T]he specification does
 not clearly disclose to the skilled artisan that the inventors... considered the...
 ratio to be part of their invention.... There is therefore no force to Purdue’s
 argument that the written description requirement was satisfied because the
 disclosure revealed a broad invention from which the [later-filed] claims carved out
 a patentable portion”). See also General Hosp. Corp. v. Sienna
 Biopharmaceuticals, Inc., 888 F.3d 1368, 1372, 126 USPQ2d 1556, 1560
 (Fed. Cir. 2018) (written description support for the claimed concentration is
 lacking where the specification discloses a range of optical densities and several
 discrete values in the range with no explicitly defined maximum concentration; and
 even if the specification may be read to convert each disclosed value into a range,
 there is insufficient written description for the entire claimed range where the
 disclosed range minimally overlaps with the claimed range). Compare Union
 Oil of Cal. v. Atl. Richfield Co., 208 F.3d 989, 997, 54 USPQ2d 1227,
 1232-33 (Fed. Cir. 2000) (Description in terms of ranges of chemical properties which
 work in combination with ranges of other chemical properties to produce an automotive
 gasoline that reduces emissions was found to provide an adequate written description
 even though the exact chemical components of each combination were not disclosed and
 the specification did not disclose any distinct embodiments corresponding to any
 claim at issue. “[T]he Patent Act and this court’s case law require only sufficient
 description to show one of skill in the . . . art that the inventor possessed the
 claimed invention at the time of filing.”).
 

 

 
 2163.06 Relationship of Written Description Requirement to New
 Matter [R-07.2022]
 

 Lack of written description is an issue that generally arises with
 respect to the subject matter of a claim. If an applicant amends or attempts to amend
 the abstract, specification or drawings of an application, an issue of new matter will
 arise if the content of the amendment is not described in the application as filed.
 Stated another way, information contained in any one of the specification, claims or
 drawings of the application as filed may be added to any other part of the application
 without introducing new matter.
 

 There are two statutory provisions that prohibit the introduction of
 new matter. The first provision is 35 U.S.C. 132 , which provides that
 no amendment shall introduce new matter into the disclosure of the invention. The second
 provision is 35 U.S.C.
 251 , which provides that no new matter shall be introduced into
 the application for reissue.
 

 I. TREATMENT OF NEW MATTER If new subject matter is added to the disclosure, whether it be in
 the abstract, the specification, or the drawings, the examiner should object to the
 introduction of new matter under 35 U.S.C. 132 or
 251 as appropriate, and require applicant to cancel the new
 matter. If new matter is added to the claims, the examiner should reject the claims
 under 35
 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph - written description requirement. In re Rasmussen, 650
 F.2d 1212, 211 USPQ 323 (CCPA 1981). The examiner should still consider the subject
 matter added to the claim in making rejections based on prior art since the new
 matter rejection may be overcome by applicant.
 

 When the claims have not been amended, per se, 
 but the specification has been amended to add new matter, a rejection of the claims
 under 35
 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, should be made whenever any of the claim limitations are affected by the
 added material.
 

 When an amendment is filed in reply to an objection or rejection
 based on 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112 , first
 paragraph, a study of the entire application is often necessary to determine whether
 or not “new matter” is involved. Applicant should therefore specifically point out
 the support for any amendments made to the disclosure.
 

 II. REVIEW OF NEW MATTER OBJECTIONS AND/OR REJECTIONS While ordinarily an objection is petitionable, and a rejection is
 appealable, when the objection is "determinative of the rejection", such as the case
 where the examiner has indicated that the disclosure contains new matter, the matter
 may be addressed by the Patent Trial and Appeal Board. See MPEP § 1201 . For
 instance, if the claims and specification or drawings contain new matter either
 directly or indirectly, and there has been both a rejection and objection by the
 examiner, the issue becomes appealable and should not be decided by petition.
 

 III. CLAIMED SUBJECT MATTER NOT DISCLOSED IN REMAINDER OF SPECIFICATION The claims as filed in the original specification are part of the
 disclosure and therefore, if an application as originally filed contains a claim
 disclosing material not disclosed in the remainder of the specification, the
 applicant may amend the specification to include the claimed subject matter.
 In re Benno, 768 F.2d 1340, 226 USPQ 683 (Fed. Cir. 1985). Form
 paragraph 7.44 may be used where originally claimed subject
 matter lacks proper antecedent basis in the specification. See MPEP §
 608.01(o) .
 

 

 
 2163.07 Amendments to Application Which Are Supported in the Original
 Description [R-08.2017]
 

 Amendments to an application which are supported in the original
 description are NOT new matter.
 

 I. REPHRASING Mere rephrasing of a passage does not constitute new matter.
 Accordingly, a rewording of a passage where the same meaning remains intact is
 permissible. In re Anderson, 471 F.2d 1237, 176 USPQ 331 (CCPA
 1973). The mere inclusion of dictionary or art recognized definitions known at the
 time of filing an application may not be considered new matter. If there are multiple
 definitions for a term and a definition is added to the application, it must be clear
 from the application as filed that applicant intended a particular definition, in
 order to avoid an issue of new matter and/or lack of written description. See, e.g.,
 Schering Corp. v. Amgen, Inc., 222 F.3d 1347, 1352-53, 55
 USPQ2d 1650, 1654 (Fed. Cir. 2000). In Schering, the original
 disclosure was drawn to recombinant DNA molecules and used the term “leukocyte
 interferon.” Shortly after the filing date, a scientific committee abolished the term
 in favor of “IFN-(a),” since the latter term more specifically identified a
 particular polypeptide and since the committee found that leukocytes also produced
 other types of interferon. The court held that the subsequent amendment to the
 specification and claims substituting the term “IFN-(a)” for “leukocyte interferon”
 merely renamed the invention and did not constitute new matter. The claims were
 limited to cover only the interferon subtype coded for by the inventor’s original
 deposits.
 

 II. OBVIOUS ERRORS An amendment to correct an obvious error does not constitute new
 matter where one skilled in the art would not only recognize the existence of error
 in the specification, but also the appropriate correction. In re Oda, 443 F.2d 1200, 170 USPQ 268 (CCPA 1971).
 

 Where a foreign priority document under 35 U.S.C. 119 
 is of record in the U.S. application file, applicant may not rely on the disclosure
 of that document to support correction of an error in the pending U.S. application.
 Ex parte Bondiou, 132 USPQ 356 (Bd. Pat. App. & Int. 1961). This
 prohibition applies regardless of the language of the foreign priority documents
 because a claim for priority is simply a claim for the benefit of an earlier filing
 date for subject matter that is common to two or more applications, and does not
 serve to incorporate the content of the priority document in the application in which
 the claim for priority is made. This prohibition does not apply where the U.S.
 application explicitly incorporates the foreign priority document by reference. For
 applications filed on or after September 21, 2004, where all or a portion of the
 specification or drawing(s) is inadvertently omitted from the U.S. application, a
 claim under 37
 CFR 1.55 for priority of a prior-filed foreign application that
 is present on the filing date of the application is considered an incorporation by
 reference of the prior-filed foreign application as to the inadvertently omitted
 portion of the specification or drawing(s), subject to the conditions and
 requirements of 37
 CFR 1.57(a) . See 37 CFR 1.57(a) and
 MPEP §
 217 .
 

 Where a U.S. application as originally filed was in a non-English
 language and an English translation thereof was subsequently submitted pursuant to
 37 CFR
 1.52(d) , if there is an error in the English translation,
 applicant may rely on the disclosure of the originally filed non-English language
 U.S. application to support correction of an error in the English translation
 document.
 

 
 2163.07(a) Inherent Function, Theory, or Advantage [R-07.2022]

 By disclosing in a patent application a device that inherently
 performs a function or has a property, operates according to a theory or has an
 advantage, a patent application necessarily discloses that function, theory or
 advantage, even though it says nothing explicit concerning it. The application may
 later be amended to recite the function, theory or advantage without introducing
 prohibited new matter. In re Reynolds, 443 F.2d 384, 170 USPQ 94 (CCPA 1971); In
 re Smythe, 480 F. 2d 1376, 178 USPQ 279 (CCPA 1973); Yeda
 Research and Dev. Co. v. Abbott GMBH & Co., 837 F.3d 1341, 120
 USPQ2d 1299 (Fed. Cir. 2016) (“Under the doctrine of inherent disclosure, when a
 specification describes an invention that has certain undisclosed yet inherent
 properties, that specification serves as adequate written description to support a
 subsequent patent application that explicitly recites the invention’s inherent
 properties.” (citing Kennecott Corp. v. Kyocera Int’l, Inc., 835
 F.2d 1419, 1423, 5 USPQ2d 1194, 1198 (Fed. Cir. 1987))). “To establish inherency, the
 extrinsic evidence ‘must make clear that the missing descriptive matter is
 necessarily present in the thing described in the reference, and that it would be so
 recognized by persons of ordinary skill. Inherency, however, may not be established
 by probabilities or possibilities. The mere fact that a certain thing may result from
 a given set of circumstances is not sufficient.’” In re Robertson, 
 169 F.3d 743, 745, 49 USPQ2d 1949, 1950-51 (Fed. Cir. 1999) (citations omitted).
 

 

 
 2163.07(b) Incorporation by Reference [R-11.2013]

 Instead of repeating some information contained in another document,
 an application may attempt to incorporate the content of another document or part
 thereof by reference to the document in the text of the specification. The
 information incorporated is as much a part of the application as filed as if the text
 was repeated in the application, and should be treated as part of the text of the
 application as filed. Replacing the identified material incorporated by reference
 with the actual text is not new matter. See 37 CFR 1.57 and
 MPEP
 § 608.01(p) for Office policy regarding incorporation by
 reference. See MPEP
 § 2181 for the impact of incorporation by reference on the
 determination of whether applicant has complied with the requirements of
 35
 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112 , second
 paragraph when 35 U.S.C. 112(f) or
 pre-AIA 35
 U.S.C. 112 , sixth paragraph is invoked.
 

 

 

 [top] 

 

 

 
 

 
 

 

 

 

 
 
 
 2101-2102-[Reserved] 

 2103-Patent Examination Process 

 2104-Requirements of 35 U.S.C. 101 
 2104.01-Barred by Atomic Energy Act 

 
 

 2105-Patent Eligible Subject Matter — Living Subject Matter 

 2106-Patent Subject Matter Eligibility 
 2106.01-[Reserved] 

 2106.02-[Reserved] 

 2106.03-Eligibility Step 1: The Four Categories of Statutory Subject Matter 

 2106.04-Eligibility Step 2A: Whether a Claim is Directed to a Judicial Exception 
 2106.04(a)-Abstract Ideas 
 2106.04(a)(1)-Examples of Claims That Do Not Recite Abstract Ideas 

 2106.04(a)(2)-Abstract Idea Groupings 

 2106.04(a)(3)-Tentative Abstract Ideas 

 
 

 2106.04(b)-Laws of Nature, Natural Phenomena & Products of Nature 

 2106.04(c)-The Markedly Different Characteristics Analysis 

 2106.04(d)-Integration of a Judicial Exception Into A Practical Application 
 2106.04(d)(1)-Evaluating Improvements in the Functioning of a Computer, or an Improvement to Any Other Technology or Technical Field in
 Step 2A Prong Two 

 2106.04(d)(2)-Particular Treatment and Prophylaxis in Step 2A Prong Two 

 
 

 
 

 2106.05-Eligibility Step 2B: Whether a Claim Amounts to Significantly More 
 2106.05(a)-Improvements to the Functioning of a Computer or To Any Other Technology or Technical Field 

 2106.05(b)-Particular Machine 

 2106.05(c)-Particular Transformation 

 2106.05(d)-Well-Understood, Routine, Conventional Activity 

 2106.05(e)-Other Meaningful Limitations 

 2106.05(f)-Mere Instructions To Apply An Exception 

 2106.05(g)-Insignificant Extra-Solution Activity 

 2106.05(h)-Field of Use and Technological Environment 

 
 

 2106.06-Streamlined Analysis 
 2106.06(a)-Eligibility is Self Evident 

 2106.06(b)-Clear Improvement to a Technology or to Computer Functionality 

 
 

 2106.07-Formulating and Supporting Rejections For Lack Of Subject Matter Eligibility 
 2106.07(a)-Formulating a Rejection For Lack of Subject Matter Eligibility 
 2106.07(a)(1)-Form Paragraphs for use in Lack of Subject Matter Eligibility Rejections 

 
 

 2106.07(b)-Evaluating Applicant’s Response 

 2106.07(c)-Clarifying the Record 

 
 

 
 

 2107-Guidelines for Examination of Applications for Compliance with the Utility Requirement 
 2107.01-General Principles Governing Utility Rejections 

 2107.02-Procedural Considerations Related to Rejections for Lack of Utility 

 2107.03-Special Considerations for Asserted Therapeutic or Pharmacological Utilities 

 
 

 2108-[Reserved] 

 2109-Inventorship 

 2109.01-Joint Inventorship 

 2110-[Reserved] 

 2111-Claim Interpretation; Broadest Reasonable Interpretation 
 2111.01-Plain Meaning 

 2111.02-Effect of Preamble 

 2111.03-Transitional Phrases 

 2111.04-“Adapted to,” “Adapted for,” “Wherein,” “Whereby,” and Contingent Clauses 

 2111.05-Functional and Nonfunctional Descriptive Material 

 
 

 2112-Requirements of Rejection Based on Inherency; Burden of Proof 
 2112.01-Composition, Product, and Apparatus Claims 

 2112.02-Process Claims 

 
 

 2113-Product-by-Process Claims 

 2114-Apparatus and Article Claims — Functional Language 

 2115-Material or Article Worked Upon by Apparatus 

 2116-Novel, Nonobvious Starting Material or End Product 
 2116.01-Novel, Nonobvious Starting Material or End Product 

 
 

 2117-Markush Claims 

 2118-2119-[Reserved] 

 2120-Rejection on Prior Art 
 2120.01-Rejections Under 35 U.S.C. 102(a)(1) and (a)(2) and Pre-AIA 35 U.S.C. 102(a), (b), or (e): Printed Publication or Patent 

 2120.02-Rejections Under 35 U.S.C. 102(a)(1) or Pre-AIA 35 U.S.C. 102(a) or (b): Knowledge by Others, or Public Use, or On Sale 

 
 

 2121-Prior Art; General Level of Operability Required to Make a Prima Facie Case 
 2121.01-Use of Prior Art in Rejections Where Operability is in Question 

 2121.02-Compounds and Compositions — What Constitutes Enabling Prior Art 

 2121.03-Plant Genetics — What Constitutes Enabling Prior Art 

 2121.04-Apparatus and Articles — What Constitutes Enabling Prior Art 

 
 

 2122-Discussion of Utility in the Prior Art 

 2123-Rejection Over Prior Art’s Broad Disclosure Instead of Preferred Embodiments 

 2124-Exception to the Rule That the Reference Must be Prior Art 
 2124.01-Tax Strategies Deemed Within the Prior Art 

 
 

 2125-Drawings as Prior Art 

 2126-Availability of a Document as a “Patent” for Purposes of Rejection Under 35 U.S.C. 102(a) or Pre-AIA 35 U.S.C. 102(a), (b),
 and (d) 
 2126.01-Date of Availability of a Patent as a Reference 

 2126.02-Scope of Reference’s Disclosure Which Can Be Used to Reject Claims When the Reference Is a “Patent” but Not a “Publication” 

 
 

 2127-Domestic and Foreign Patent Applications as Prior Art 

 2128-“Printed Publications” as Prior Art 
 2128.01-Level of Public Accessibility Required 

 2128.02-Date Publication Is Available as a Reference 

 
 

 2129-Admissions as Prior Art 

 2130-[Reserved] 

 2131-Anticipation — Application of 35 U.S.C. 102 
 2131.01-Multiple Reference 35 U.S.C. 102 Rejections 

 2131.02-Genus-Species Situations 

 2131.03-Anticipation of Ranges 

 2131.04-Secondary Considerations 

 2131.05-Nonanalogous or Disparaging Prior Art 

 
 

 2132-Pre-AIA 35 U.S.C. 102(a) 
 2132.01-Overcoming a Pre-AIA 35 U.S.C. 102(a) Rejection based on a Printed Publication or Patent 

 
 

 2133-Pre-AIA 35 U.S.C. 102(b) 
 2133.01-Rejections of Continuation-In-Part (CIP) Applications 

 2133.02-Rejections Based on Publications and Patents 
 2133.02(a)-Overcoming a Pre-AIA 35 U.S.C. 102(b) Rejection Based on a Printed Publication or Patent 

 
 

 2133.03-Rejections Based on “Public Use” or “On Sale” 
 2133.03(a)-“Public Use” 

 2133.03(b)-“On Sale” 

 2133.03(c)-The “Invention” 

 2133.03(d)-“In This Country” 

 2133.03(e)-Permitted Activity; Experimental Use 
 2133.03(e)(1)-Commercial Exploitation 

 2133.03(e)(2)-Intent 

 2133.03(e)(3)-“Completeness” of the Invention 

 2133.03(e)(4)-Factors Indicative of an Experimental Purpose 

 2133.03(e)(5)-Experimentation and Degree of Supervision and Control 

 2133.03(e)(6)-Permitted Experimental Activity and Testing 

 2133.03(e)(7)-Activity of an Independent Third Party Inventor 

 
 

 
 

 
 

 2134-Pre-AIA 35 U.S.C. 102(c) 

 2135-Pre-AIA 35 U.S.C. 102(d) 
 2135.01-The Four Requirements of Pre-AIA 35 U.S.C. 102(d) 

 
 

 2136-Pre-AIA 35 U.S.C. 102(e) 
 2136.01-Status of Unpublished or Published as Redacted U.S. Application as a Reference Under Pre-AIA 35 U.S.C. 102(e) 

 2136.02-Content of the Prior Art Available Against the Claims 

 2136.03-Critical Reference Date 

 2136.04-Different Inventive Entity; Meaning of “By Another” 

 2136.05-Overcoming a Rejection Under Pre-AIA 35 U.S.C. 102(e) 
 2136.05(a)-Antedating a Pre-AIA 35 U.S.C. 102(e) Reference 

 2136.05(b)-Showing The Reference Is Describing An Inventor's Or At Least One Joint Inventor's Own Work 

 
 

 
 

 2137-Pre-AIA 35 U.S.C. 102(f) 
 2137.01-[Reserved] 

 2137.02-[Reserved] 

 
 

 2138-Pre-AIA 35 U.S.C. 102(g) 
 2138.01-Interference Practice 

 2138.02-“The Invention Was Made in This Country” 

 2138.03-“By Another Who Has Not Abandoned, Suppressed, or Concealed It” 

 2138.04-“Conception” 

 2138.05-“Reduction to Practice” 

 2138.06-“Reasonable Diligence” 

 
 

 2139-Rejections Under Pre-AIA 35 U.S.C. 102 
 2139.01-Effective Filing Date of a Claimed Invention Under Pre-AIA 35 U.S.C. 102 

 2139.02-Determining Whether To Apply Pre-AIA 35 U.S.C. 102(a), (b), or (e) 

 2139.03-Form Paragraphs for Use in Rejections Under Pre-AIA 35 U.S.C. 102 

 
 

 2140-[Reserved] 

 2141-Examination Guidelines for Determining Obviousness Under 35 U.S.C. 103 
 2141.01-Scope and Content of the Prior Art 
 2141.01(a)-Analogous and Nonanalogous Art 

 
 

 2141.02-Differences Between Prior Art and Claimed Invention 

 2141.03-Level of Ordinary Skill in the Art 

 
 

 2142-Legal Concept of Prima Facie Obviousness 

 2143-Examples of Basic Requirements of a Prima Facie Case of Obviousness 
 2143.01-Suggestion or Motivation To Modify the References 

 2143.02-Reasonable Expectation of Success Is Required 

 2143.03-All Claim Limitations Must Be Considered 

 
 

 2144-Supporting a Rejection Under 35 U.S.C. 103 
 2144.01-Implicit Disclosure 

 2144.02-Reliance on Scientific Theory 

 2144.03-Reliance on Common Knowledge in the Art or “Well Known” Prior Art 

 2144.04-Legal Precedent as Source of Supporting Rationale 

 2144.05-Obviousness of Similar and Overlapping Ranges, Amounts, and Proportions 

 2144.06-Art Recognized Equivalence for the Same Purpose 

 2144.07-Art Recognized Suitability for an Intended Purpose 

 2144.08-Obviousness of Species When Prior Art Teaches Genus 

 2144.09-Close Structural Similarity Between Chemical Compounds (Homologs, Analogues, Isomers) 

 
 

 2145-Consideration of Applicant’s Rebuttal Arguments and Evidence 

 2146-Pre-AIA 35 U.S.C. 103(c) 
 2146.01-Prior Art Disqualification Under Pre-AIA 35 U.S.C. 103(c) 

 2146.02-Establishing Common Ownership or Joint Research Agreement Under Pre-AIA 35 U.S.C. 103(c) 

 2146.03-Examination Procedure With Respect to Pre-AIA 35 U.S.C. 103(c) 
 2146.03(a)-Provisional Rejection (Obviousness) Under 35 U.S.C. 103(a) Using Provisional Prior Art Under Pre-AIA 35 U.S.C. 102(e) 

 
 

 
 

 2147-Biotechnology Process Applications; Pre-AIA 35 U.S.C. 103(b) 

 2148-Form Paragraphs for Use in Rejections Under Pre-AIA 35 U.S.C. 103 

 2149-[Reserved] 

 2150-Examination Guidelines for 35 U.S.C. 102 and 103 as Amended by the First Inventor To File Provisions of the Leahy-Smith America
 Invents Act 

 2151-Overview of the Changes to 35 U.S.C. 102 and 103 in the AIA 

 2152-Detailed Discussion of AIA 35 U.S.C. 102(a) and (b) 
 2152.01-Effective Filing Date of the Claimed Invention 

 2152.02-Prior Art Under AIA 35 U.S.C. 102(a)(1) (Patented, Described in a Printed Publication, or in Public Use, on Sale, or Otherwise
 Available to the Public) 
 2152.02(a)-Patented 

 2152.02(b)-Described in a Printed Publication 

 2152.02(c)-In Public Use 

 2152.02(d)-On Sale 

 2152.02(e)-Otherwise Available to the Public 

 2152.02(f)-No Requirement of “By Others” 

 
 

 2152.03-Admissions 

 2152.04-The Meaning of “Disclosure” 

 2152.05-Determining Whether To Apply 35 U.S.C. 102(a)(1) or 102(a)(2) 

 2152.06-Overcoming a 35 U.S.C. 102(a)(1) or 102(a)(2) Rejection 

 2152.07-Form Paragraphs for Use in Rejections Under AIA 35 U.S.C. 102 

 
 

 2153-Prior Art Exceptions Under 35 U.S.C. 102(b)(1) to AIA 35 U.S.C. 102(a)(1) 
 2153.01-Prior Art Exception Under AIA 35 U.S.C. 102(b)(1)(A) To AIA 35 U.S.C. 102(a)(1) (Grace Period Inventor-Originated Disclosure
 Exception) 
 2153.01(a)-Grace Period Inventor-Originated Disclosure Exception 

 2153.01(b)-[Reserved] 

 
 

 2153.02-Prior Art Exception Under AIA 35 U.S.C. 102(b)(1)(B) to AIA 35 U.S.C. 102(a)(1) (Inventor-Originated Prior Public Disclosure
 Exception) 

 
 

 2154-Provisions Pertaining to Subject Matter in a U.S. Patent or Application Effectively Filed Before the Effective Filing Date
 of the Claimed Invention 
 2154.01-Prior Art Under AIA 35 U.S.C. 102(a)(2) “U.S. Patent Documents” 
 2154.01(a)-WIPO Published Applications 

 2154.01(b)-Determining When Subject Matter Was Effectively Filed Under AIA 35 U.S.C. 102(d) 

 2154.01(c)-Requirement Of “Names Another Inventor” 

 2154.01(d)-Provisional Rejections Under 35 U.S.C. 102(a)(2); Reference Is a Copending U.S. Patent Application 

 
 

 2154.02-Prior Art Exceptions Under 35 U.S.C. 102(b)(2) to AIA 35 U.S.C. 102(a)(2) 
 2154.02(a)-Prior Art Exception Under AIA 35 U.S.C. 102(b)(2)(A) to AIA 35 U.S.C. 102(a)(2) (Inventor-Originated Disclosure Exception) 

 2154.02(b)-Prior Art Exception Under AIA 35 U.S.C. 102(b)(2)(B) to AIA 35 U.S.C. 102(a)(2) (Inventor-Originated Prior Public Disclosure
 Exception) 

 2154.02(c)-Prior Art Exception Under AIA 35 U.S.C. 102(b)(2)(C) to AIA 35 U.S.C. 102(a)(2) (Common Ownership or Obligation of Assignment) 

 
 

 
 

 2155-Use of Affidavits or Declarations Under 37 CFR 1.130 To Overcome Prior Art Rejections 
 2155.01-Showing That the Disclosure Was Made by the Inventor or a Joint Inventor 

 2155.02-Showing That the Subject Matter Disclosed Had Been Previously Publicly Disclosed by the Inventor or a Joint Inventor 

 2155.03-Showing That the Disclosure was Made, or That Subject Matter had Been Previously Publicly Disclosed, by Another Who Obtained
 the Subject Matter Disclosed Directly or Indirectly From the Inventor or a Joint Inventor 

 2155.04-Enablement 

 2155.05-Who May File an Affidavit or Declaration Under 37 CFR 1.130 

 2155.06-Situations in Which an Affidavit or Declaration Is Not Available 

 
 

 2156-Joint Research Agreements 

 2157-Improper Naming of Inventors 

 2158-AIA 35 U.S.C. 103 
 2158.01-Form Paragraphs for Use in Rejections Under AIA 35 U.S.C. 103 

 
 

 2159-Applicability Date Provisions and Determining Whether an Application Is Subject to the First Inventor To File Provisions of
 the AIA 
 2159.01-Applications Filed Before March 16, 2013 

 2159.02-Applications Filed on or After March 16, 2013 

 2159.03-Applications Subject to the AIA but Also Containing a Claimed Invention Having an Effective Filing Date Before March 16, 2013 

 2159.04-Applicant Statement in Transition Applications Containing a Claimed Invention Having an Effective Filing Date on or After
 March 16, 2013 

 
 

 2160-[Reserved] 

 2161-Three Separate Requirements for Specification Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph 
 2161.01-Computer Programming, Computer Implemented Inventions, and 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph 

 
 

 2162-Policy Underlying 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph 

 2163-Guidelines for the Examination of Patent Applications Under the 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, first paragraph,
 “Written Description” Requirement 
 2163.01-Support for the Claimed Subject Matter in Disclosure 

 2163.02-Standard for Determining Compliance With the Written Description Requirement 

 2163.03-Typical Circumstances Where Adequate Written Description Issue Arises 

 2163.04-Burden on the Examiner with Regard to the Written Description Requirement 

 2163.05-Changes to the Scope of Claims 

 2163.06-Relationship of Written Description Requirement to New Matter 

 2163.07-Amendments to Application Which Are Supported in the Original Description 
 2163.07(a)-Inherent Function, Theory, or Advantage 

 2163.07(b)-Incorporation by Reference 

 
 

 
 

 2164-The Enablement Requirement 
 2164.01-Test of Enablement 
 2164.01(a)-Undue Experimentation Factors 

 2164.01(b)-How to Make the Claimed Invention 

 2164.01(c)-How to Use the Claimed Invention 

 
 

 2164.02-Working and Prophetic Examples 

 2164.03-Relationship of Predictability of the Art and the Enablement Requirement 

 2164.04-Burden on the Examiner Under the Enablement Requirement 

 2164.05-Determination of Enablement Based on Evidence as a Whole 
 2164.05(a)-Specification Must Be Enabling as of the Filing Date 

 2164.05(b)-Specification Must Be Enabling to Persons Skilled in the Art 

 
 

 2164.06-Quantity of Experimentation 
 2164.06(a)-Examples of Enablement Issues-Missing Information 

 2164.06(b)-Examples of Enablement Issues — Biological and Chemical Cases 

 2164.06(c)-Examples of Enablement Issues – Computer Programming Cases 

 
 

 2164.07-Relationship of Enablement Requirement to Utility Requirement of 35 U.S.C. 101 

 2164.08-Enablement Commensurate in Scope With the Claims 
 2164.08(a)-Single Means Claim 

 2164.08(b)-Inoperative Subject Matter 

 2164.08(c)-Critical Feature Not Claimed 

 
 

 
 

 2165-The Best Mode Requirement 
 2165.01-Considerations Relevant to Best Mode 

 2165.02-Best Mode Requirement Compared to Enablement Requirement 

 2165.03-Requirements for Rejection for Lack of Best Mode 

 2165.04-Examples of Evidence of Concealment 

 
 

 2166-Rejections Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph 

 2167-2170-[Reserved] 

 2171-Two Separate Requirements for Claims Under 35 U.S.C. 112(b) or Pre-AIA 35 U.S.C. 112, Second Paragraph 

 2172-Subject Matter Which the Inventor or a Joint Inventor Regards as The Invention 
 2172.01-Unclaimed Essential Subject Matter 

 
 

 2173-Claims Must Particularly Point Out and Distinctly Claim the Invention 
 2173.01-Interpreting the Claims 

 2173.02-Determining Whether Claim Language is Definite 

 2173.03-Correspondence Between Specification and Claims 

 2173.04-Breadth Is Not Indefiniteness 

 2173.05-Specific Topics Related to Issues Under 35 U.S.C. 112(b) or Pre-AIA 35 U.S.C. 112, Second Paragraph 
 2173.05(a)-New Terminology 

 2173.05(b)-Relative Terminology 

 2173.05(c)-Numerical Ranges and Amounts Limitations 

 2173.05(d)-Exemplary Claim Language (“for example,” “such as”) 

 2173.05(e)-Lack of Antecedent Basis 

 2173.05(f)-Reference to Limitations in Another Claim 

 2173.05(g)-Functional Limitations 

 2173.05(h)-Alternative Limitations 

 2173.05(i)-Negative Limitations 

 2173.05(j)-Old Combination 

 2173.05(k)-Aggregation 

 2173.05(l)-[Reserved] 

 2173.05(m)-Prolix 

 2173.05(n)-Multiplicity 

 2173.05(o)-Double Inclusion 

 2173.05(p)-Claim Directed to Product-By- Process or Product and Process 

 2173.05(q)-“Use” Claims 

 2173.05(r)-Omnibus Claim 

 2173.05(s)-Reference to Figures or Tables 

 2173.05(t)-Chemical Formula 

 2173.05(u)-Trademarks or Trade Names in a Claim 

 2173.05(v)-Mere Function of Machine 

 
 

 2173.06-Practice Compact Prosecution 

 
 

 2174-Relationship Between the Requirements of 35 U.S.C. 112(a) and (b) or Pre-AIA 35 U.S.C. 112, First and Second Paragraphs 

 2175-Form Paragraphs for Use in Rejections Under 35 U.S.C. 112(b) or Pre-AIA 35 U.S.C. 112, Second Paragraph 

 2176-2180-[Reserved] 

 2181-Identifying and Interpreting a 35 U.S.C. 112(f) or Pre-AIA 35 U.S.C. 112, Sixth Paragraph Limitation 

 2182-Search and Identification of the Prior Art 

 2183-Making a Prima Facie Case of Equivalence 

 2184-Determining Whether an Applicant Has Met the Burden of Proving Nonequivalence After a Prima Facie Case Is Made 

 2185-Related Issues Under 35 U.S.C. 112(a) or (b) and Pre-AIA 35 U.S.C. 112, First or Second Paragraphs 

 2186-Relationship to the Doctrine of Equivalents 

 2187-Form Paragraphs for Use Relating to 35 U.S.C. 112(f) or Pre-AIA 35 U.S.C. 112, Sixth Paragraph 

 2188-2189-[Reserved] 

 2190-Prosecution Laches and Res Judicata 

 

 

 
 

 
 
 

 
 

 

 
 
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 03/09/2026 20:49:33