<PAGE>



                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 10-K/A
     PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934

           -----                      -----
             X                    ANNUAL REPORT
           -----     FOR THE FISCAL YEAR ENDED DECEMBER 31, 1996

                                    -- or --
           -----
                                TRANSITION REPORT
           -----     FOR THE TRANSITION PERIOD FROM ____ TO ____

                        -------------------------------
                     
                            OSTEX INTERNATIONAL, INC.
                 NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER

                                     0-25250
                             COMMISSION FILE NUMBER

                               STATE OF WASHINGTON
          STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION

                                   91-1450247
                     I.R.S. EMPLOYER IDENTIFICATION NUMBER

          2203 AIRPORT WAY SOUTH, SUITE 400, SEATTLE, WASHINGTON 98134
                                  206-292-8082
           ADDRESS AND TELEPHONE NUMBER OF PRINCIPAL EXECUTIVE OFFICES

          Securities registered pursuant to Section 12(b) of the Act:
                    (none)                         (none)
                Title of Class       Each Exchange on Which Registered

          Securities registered pursuant to Section 12(g) of the Act:
                          COMMON STOCK, $.01 PAR VALUE
                                 Title of Class

    Indicate  by  checkmark  whether  the  registrant  (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange
Act of 1934 during the preceding 12 months (or for such shorter  period that the
registrant was required to file such reports),  and (2) has been subject to such
filing requirements for the past 90 days. 

     Yes   X         No
         ----           ----

    Indicate by check mark if disclosure of delinquent  filers  pursuant to Item
405 of Regulation S-K is not contained herein,  and will not be contained,
to the best of  registrant's  knowledge,  in  definitive  proxy  or  information
statements  incorporated  by  reference  in Part  III of this  Form  10-K or any
amendment to this Form 10-K.

           X         
         ----     


<PAGE>


This amendment is filed to correct portions of the Exhibit Index and redactions
in exhibits 10.4A, 10.4B, 10.15A, and 10.15B.





       (C)  EXHIBIT INDEX (7)

       Exhibit
       Number      Description
       -------     ---------------------------------------------------
       3.1        Articles of Incorporation, as amended, dated January 1997.

       (1)3.2      Bylaws, as amended

       (1)4.1      Specimen Common Stock Certificate

                   Stock Purchase Agreements ("Terms and Provisions"  included 
                   in Exhibit 3.1)
       (1)4.2A       Series A Stock Purchase  Agreement  dated September 1989 
       (1)4.2B       Series B Stock Purchase Agreement dated June 1992
       (1)4.2C       Series C Stock Purchase Agreement dated August 1993

       (1)4.3      Form of CS First Boston Corporation Warrant

       (1)4.4      Form of Invemed Associates, Inc. Warrant

       (2)4.5      Shareholder Rights Agreement dated January 21, 1997

       (1)10.1A    Amended and Restated Stock Option Plan
       (1)10.1B    Form of Employee Stock Option Agreement
       (1)10.1C    Form of Director's Stock Option Agreement

       (1)10.2     Directors' Nonqualified Stock Option Plan

       (1)10.3     1994 Stock Option Plan

                   Agreements with Hologic, Inc.
       (3)10.4A      Co-Promotion and Sales Representation Agreement dated 
                     January 14, 1997
       (3)10.4B      Joint Development, License and Supply Agreement dated 
                     January 14, 1997

       (1)10.5     Form of  Indemnification Agreement with officers and 
                   directors

       (1)10.6     Form of Employee Confidentiality and Invention Agreement

                   Agreements with H. Raymond Cairncross
       (1)10.7A      Employment Agreement dated April 15, 1994
       (1)10.7B      Stock Option Agreements dated June 6, 1991, July 1, 1993, 
                     July 1, 1994, April 15, 1994

       (1)10.9     Asset Purchase and Sale Agreement dated May 31, 1994 with 
                   Hybrilogic Corporation

       (1)10.10    Cooperation Agreement dated August 11, 1993 with 
                   Merck & Co., Inc.

                   Agreements with Mochida Pharmaceutical Co., Inc.
       (1)10.12A     Research and Development Agreement dated August 1992
       (1)10.12B     Osteomark License Agreement Dated August 1992
       (1)10.12C     Stock Purchase Agreement dated November 22, 1994

                   Agreements with The Washington Research Foundation
       (1)10.13A     Restated Exclusive License Agreement effective June 19, 
                     1992 (Urinary Assay for Measuring Bone Resorption)
       (1)10.13B     Amendment to Restated Exclusive License Agreement effective
                     January 1, 1993
       (1)10.13C     Second Amendment effective June 2, 1994

       (1)10.14      Exclusive License Agreement dated February 10, 1994 (O-CSF)

<PAGE>

       Exhibit
       Number      Description
       -------     ---------------------------------------------------
                   Agreements with the University of Washington
       (3)10.15A     Research Agreement dated July 1, 1996 (Molecular Markers of
                     Connective Tissue Degradation)
       (3)10.15B     Research Agreement dated October 1, 1996 (Role of O-CSF in 
                     Osteoclast Regulation)

       (1)10.16A   Know-How Transfer and Consulting Agreement dated 
                   September 18, 1989 with David R. Eyre, Ph.D.
       (1)10.16B   Extension and Amendment dated May 1, 1992

       (1)10.17    Amended and Restated Know-How Transfer and Consulting 
                   Agreement dated February 22, 1993 with Minako Y. Lee, M.D.

       (1)10.19    Osteomark EIA Exclusive Distribution License Agreement dated 
                   March 28, 1994 with Technogenetics S.R.L. (division of 
                   Recordati Pharmaceutical)

       (1)10.20    Osteomark EIA Distribution  License Agreement dated July 12,
                   1994 with BRAHMS Diagnostic (formerly Henning Berlin GMBH)

       (1)10.21    Osteomark EIA Exclusive Distribution License Agreement dated 
                   May 4, 1994 with Shield Diagnostics (Limited)

       (1)10.22    Osteomark EIA Exclusive Distribution License Agreement dated 
                   July 1, 1994 with DSL Diagnostic Products, Inc. 
                   (dba INTER Medico)

       (1)10.23    Osteomark Agreement dated February 12, 1993, as amended 
                   May 10, 1994, with Nichols Institute Reference Laboratory

       (1)10.24    Osteomark EIA Exclusive Distribution License Agreement dated 
                   September 1, 1994 with Immuno Diagnostics

       (1)10.25    License Agreement dated July 8, 1994  with Endrocrine 
                   Sciences

       (1)10.26    License Agreement dated August 1994 with Pacific Biometrics,
                   Inc.

                   Lease Agreements
       (4)10.27A     Lease Agreement dated October 2, 1995, with David A. Sabey 
                     and Sandra L. Sabey
       10.27B        First Amendment of Lease dated October 15, 1996, with the 
                     City of Seattle, successor-in-interest to David A. Sabey 
                     and Sandra L. Sabey

                   Agreements with Johnson & Johnson Clinical Diagnostics, Inc.
       (5)10.28A     Distribution Agreement dated June 7, 1995
       (5)10.28B     Research, Development, License and Supply Agreement dated 
                     June 7, 1995

       (4)10.29    Clinical Laboratory Services License and Supply Agreement 
                   dated October 25, 1995, with SmithKline Beecham Clinical 
                   Laboratories, Inc.


<PAGE>



       Exhibit
       Number      Description
       -------     ---------------------------------------------------

       (4)10.30    Promotion Agreement dated September 20, 1995 with 
                   Wyeth-Ayerst Laboratories

       (6)10.31    Agreement with Laboratory Corporation of American Holdings 
                   (LabCorp), dated January 11, 1996

       13.0        Annual Report to stockholders for the year-ended 
                   December 31, 1996

       27.1        Financial Data Schedule

Notes to the Exhibits.

(1)    Incorporated herein by reference from Item 16(a) of Registrant's Form S-1
Registration Statement as declared effective January 24, 1995 (No. 33-86118).
(2)     Incorporated herein by reference from Form 8-A filed with the S.E.C.
in January 1997.
(3)     Confidential treatment requested.  Exhibit omits information that has
been filed separately with the Securities and Exchange Commission.          
(4)     Incorporated herein by reference from Form 10-K filed with the S.E.C
for the year ended December 31,1995.
(5)     Incorporated herein by reference from Form 10-Q filed with the S.E.C
for the quarter ended June 30, 1995.
(6)     Incorporated herein by reference from Form 10-Q filed with the S.E.C.
for the quarter ended March 31, 1996.
(7)     Copies of exhibits may be obtained at prescribed  rates from the Public
Reference  Section of the Securities  and Exchange  Commission at 450 5th Street
NW, Room 1024, Washington, D.C., 20549.


<PAGE>




                                   SIGNATURES

    Pursuant  to the  requirements  of  Section  13 or 15(d)  of the  Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned. 

                                              OSTEX INTERNATIONAL, INC.

                                          By  /S/ THOMAS A. BOLOGNA
                                            ----------------------------
                                               Thomas A. Bologna 
                                         President, Chief Executive Officer 
                                       and Member of the Board of Directors 


    Pursuant to the  requirements  of the Securities  Exchange Act of 1934, this
report  has  been  signed  below  by the  following  persons  on  behalf  of the
Registrant and in the capacities and on the dates indicated.


      SIGNATURE                       CAPACITIES                       DATE
      ---------                       ----------                       ----

/S/ THOMAS A. BOLOGNA      President, Chief Executive Officer
------------------------- and Member of the Board of Directors October 16, 1997
  Thomas A. Bologna          (principal executive officer)


/S/ Robert M. Littauer           Senior Vice President,        October 16, 1997
-------------------------      Finance and Administration
   Robert M. Littauer          (principal financial and 
                              principal accounting officer)