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                                                                   EXHIBIT 10.61

                         CALYPTE BIOMEDICAL CORPORATION
                             1265 Harbor Bay Parkway
                                Alameda, CA 94502

                                October 18, 1999

David Collins
PMB # 224
774 Mays Blvd., # 10
Incline Village, NV 89451

         Re:      CONSULTING AGREEMENT WITH CALYPTE

Dear Dave:

         Upon your signature at the end of this letter where indicated, this
letter will be the binding agreement (the "AGREEMENT"), effective as of October
18, 1999 (the "EFFECTIVE DATE"), between Calypte Biomedical Corporation
("CALYPTE") and you with respect to your provision of service as a consultant to
Calypte as provided in this letter; the Basic Retained Services described in
Section 1(a) hereof and any Additional Services defined in Section 1(b) hereof
are referred to herein collectively as the "SERVICES".

         1.       SERVICES.

                  (a) BASIC RETAINED SERVICES. Subject to the terms and
conditions of this Agreement, you hereby are retained by Calypte as a consultant
to Calypte from the Effective Date until terminated as provided herein, to
provide (i) an aggregate of five (5) days of Services (the "BASIC RETAINED
SERVICES") per calendar month during the term hereof, commencing with the month
of October, 1999 (with a "day of Services" being considered for such purposes as
eight (8) hours, and with travel time while on business for Calypte, and while
travelling from your home outside of California to Calypte's principal offices
for purposes of rendering such Basic Retained Services, in each case being
counted as one-half time), and (ii) such additional days of Additional Services,
as provided in and defined in Section 1(b) hereof, as you may agree with Calypte
upon Calypte's reasonable and good faith request to you, in each case with
respect to Calypte's business, and such other matters commensurate with the
office of Chief Executive Officer, all as may be requested from time to time
during the term hereof orally or in writing by the Board of Directors (the
"BOARD") of Calypte or by the President of Calypte.

                  (b) ADDITIONAL SERVICES. In addition to the Basic Retained
Services rendered as described in Section 1(a) hereof, you will render such
number of days of Services (the "ADDITIONAL SERVICES") as are so requested in
good faith by Calypte, by its Board or President (with a "day of Services" being
considered for such purposes as eight (8) hours, and with travel time while on
business for Calypte, and while travelling from your home outside of California
to Calypte's principal offices for purposes of rendering such Basic Retained
Services, in each case being counted as one-half time).


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David Collins
October 18, 1999
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                  (c) CERTAIN CONDITIONS CONCERNING SERVICE AS A DIRECTOR OF
CALYPTE. You hereby agree that you will serve as a member of the Board if so
asked and for so long as you are duly elected thereto. The number of days you
spend rendering Services to Calypte hereunder will be in addition to time you
spend to discharge your customary duties as a Director of Calypte, including
time to prepare for and attend meetings of the Board and of Board Committees
upon which you serve, during such time as you are serving as a Director of
Calypte. Any compensation you may receive for your services as a Director of
Calypte, such as indemnification, stock, and/or stock options and other benefits
from the Company as are made available from time to time by the Company to other
Directors, will be separate from this Agreement.

                  (d) SCHEDULING; LOCATION. The days upon which Calypte will
require your Services will be based upon dates and times mutually agreeable
between you and Calypte. Calypte will provide as much advance notice as possible
to you of the dates and times required, and you will make every reasonable
effort to make yourself available during such dates. Calypte will not require
you to render such services at dates, times or places that would reasonably
interfere with other work commitments you may have. You may render the Services
by telephone and/or e-mail, and/or on-site at Calypte's headquarters in the San
Francisco Bay Area, and/or at other locations, as determined in good faith by
Calypte after consultation with you as to mutual convenience and the particular
Services required.

                  (e) REPORTING. You will report to the Board, but you will
render Services upon the request of the Board and/or of the President of
Calypte.

                  (f) OTHER ACTIVITIES. Calypte acknowledges and agrees that,
while you will devote such time and effort as is necessary to discharge your
duties hereunder, you will not be providing your full-time services to Calypte,
and that you may consult with or become an employee of other entities as you
wish (including but not limited to accepting full time employment), subject to
your obligations as to confidential and proprietary information of Calypte as
set forth in this Agreement.

                  (g) NONASSIGNABILITY OF YOUR SERVICES. You may not assign or
subcontract your duties or rights under this Agreement without the prior written
consent of Calypte signed by its President or Chairman of the Board.

         2.       COMPENSATION; EXPENSE REIMBURSEMENT; LODGING AND AUTOMOBILE;
STOCK OPTIONS.

                  (a) RETAINER FOR BASIC RETAINED SERVICES; PAYMENT FOR
ADDITIONAL SERVICES. Calypte will pay you a retainer, in cash, at the beginning
of each calendar month commencing with the month of October, 1999 (provided that
such consulting fee will be paid no later than October 19, 1999 for such month),
in the amount of five thousand dollars ($5,000.00) for your Basic Retained
Services, which is one thousand dollars ($1,000.00) per day of such Basic
Retained Services. In addition, Calypte will pay you a consulting fee in cash
for any Additional


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David Collins
October 18, 1999
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Services you may render, within thirty (30) days after the close of each
calendar month during which you render such Additional Services, at the rate of
one thousand dollars ($1,000.00) per day of such Additional Services.

                  (b) EXPENSE REIMBURSEMENT; LODGING AND AUTOMOBILE. Calypte
will reimburse you for all reasonable, ordinary and necessary travel and
entertainment expenses incurred by you in conjunction with your services to
Calypte hereunder. While you are rendering Services in the San Francisco Bay
Area, Calypte will provide lodging for you, or will reimburse you for lodging,
in a business hotel or business traveler long-term stay facility reasonably
convenient to Calypte's offices, and will reimburse you for that portion of your
automobile lease apportioned for your use of your automobile on business of
Calypte. Any such expense, including without limitation lodging or automobile
lease reimbursement will, to the extent not specifically provided in this
Section 2(b), be consistent with Calypte's then-standard reimbursement policy,
and, as applicable, travel policy, and will be made as to a given expense only
if you have submitted commercially customary support documentation to Calypte
therefor.

                  (c) STOCK OPTION. Within fifteen (15) days after the Effective
Date, Calypte will, by action of its Board, grant to you a nonqualified stock
option (the "OPTION"), under Calypte's then current Equity Incentive Plan (the
"PLAN"), for a total of one hundred fifty thousand (150,000) shares of Common
Stock of Calypte, subject to the following:

                            (i)   EXERCISEABILITY; REPURCHASE RIGHT. Fifty
thousand (50,000) shares under the Option will be immediately vested and
exerciseable. The Option will become exerciseable (A) at the sixth-month
anniversary of the Effective Date (April 18, 2000), as to an additional fifty
thousand (50,000) shares, and (B) at the first anniversary of the Effective Date
(October 18, 2000), for the remaining fifty thousand (50,000) shares, provided
you are, at such sixth-month anniversary, and one-year anniversary,
respectively, then still employed by or serving as a consultant to Calypte,
including serving as a Director. The Option otherwise will be granted under such
customary documentation as to form of grant and exercise as is used for other
nonqualified stock options granted under the Plan, provided that such grant
documentation will contain a provision that if a Sale of Assets or Change of
Control, as hereinafter defined, occurs prior to October 18, 2000 (which is the
first anniversary of the Effective Date), and provided your employment with
Calypte has not been terminated for cause within the ninety (90) days preceding
the date of the relevant event, then the Option will automatically become
exerciseable as to all shares for which it is not then otherwise exerciseable,
as of the date of the Sale of Assets or Change of Control. For purposes of this
Agreement, a "SALE OF ASSETS OR CHANGE OF CONTROL" means (a) the closing of a
sale by Calypte of all or substantially all of its assets, in one or a series of
related transactions (a sale of assets), or (b) the date upon which those
persons who, immediately prior to such date, held fifty percent (50%) or more of
the outstanding voting securities of Calypte, immediately after such date hold
less than fifty percent (50%) of the outstanding voting securities of Calypte (a
change of control), provided that such event is the result of a sale or other
transfer, including a merger or other reorganization involving Calypte, of
equity securities from one or more parties to one or more other parties, and
provided that this provision will not apply in the event of the issuance by
Calypte of its equity securities in an


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David Collins
October 18, 1999
Page 4


equity financing, whether as a private placement or in any public offering by
Calypte of its securities.

                            (ii)  EXERCISE PRICE; PAYMENT.  The Option will have
an exercise price equal to the fair market value per share of the Common Stock
as determined in good faith by the Board as of the date of grant. The grant will
provide that you may pay for such shares upon such methods as are permitted
under the Plan for nonqualified stock options.

         3.       OUR RELATIONSHIP.

                  (a) INDEPENDENT CONTRACTOR. In performance of your services
under this Agreement, you will be an independent contractor of, and are not an
agent or employee of, and have no authority to bind, Calypte by contract or
otherwise.

                  (b) EMPLOYMENT TAXES AND BENEFITS. You will report as
self-employment income all compensation you received pursuant to this Agreement,
including the fair market value of the Shares. You will indemnify Calypte and
hold it harmless from and against all claims, damages, losses and expenses,
relating to any obligation imposed by law on Calypte to pay any withholding
taxes, social security (except for employer's share of social security, if any),
unemployment or disability insurance, or similar items in connection with
compensation received by you pursuant to this Agreement. You will not be
entitled to receive any vacation or illness payments, or to participate in any
plans, arrangements, or distributions by Calypte pertaining to any bonus, stock
option, profit sharing, insurance or similar benefits for Calypte's employees,
except as provided herein or as otherwise specifically approved by the Board.

                  (c) NO REMUNERATION AS TO PRODUCTS. You will receive no
royalty or other remuneration on the production or distribution of any products
developed by the Company or by you in connection with or based upon the
Services.

         4.       INDEMNIFICATION.

                  (a) BY YOU. To the extent determined by a tribunal of
competent jurisdiction (arbitral or judicial), not subject to further appeal,
you will indemnify Calypte and hold it harmless from and against all claims,
damages, losses and expenses, including court costs and reasonable fees and
expenses of attorneys, expert witnesses, and other professionals, arising out of
or resulting from:

                            (i)   Any action by a third party against Calypte
to the extent based on any claim that any Services performed under this
Agreement, or their results, to your actual knowledge (A) infringe a patent,
trademark, copyright or other proprietary right, and/or (B) violate a trade
secret of such third party; and

                            (ii)  Any action by a third party to the extent
based on any conduct by you in performing Services under this Agreement which
results in any of the following and for


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David Collins
October 18, 1999
Page 5


which such tribunal determines you to be liable to Calypte under applicable law:
(A) any bodily injury, sickness, disease or death; (B) any injury or destruction
to tangible or intangible property (including computer programs and data) or any
loss of use resulting therefrom; or (C) any violation of any statute, ordinance,
or regulation.

                  (b) BY CALYPTE. To the extent legally permitted, and not in
derogation of your obligations under Section 4(a) hereof: (i) you will be
considered as subject to the indemnity provisions of Calypte's Certificate of
Incorporation and Bylaws, a copy of which will be furnished to you upon request,
and (ii) Calypte will indemnify you and hold you harmless from and against all
claims, damages, losses and expenses, including court costs and reasonable fees
and expenses of attorneys, expert witnesses, and other professionals, arising
out of or resulting from any action by a third party against Calypte or you, or
both, in connection with or based upon the performance by you of the Services,
or their result.

         5. PROPERTY OF CALYPTE.

                  (a)    DEFINITIONS.  For the purposes of this Agreement:

                            (i)   "INVENTIONS" means any and all inventions,
ideas, designs, circuits, schematics, formulas, algorithms, trade secrets, works
of authorship, mask works, developments, methods, processes, techniques,
improvements, and related know-how in the field of research, development and
commercialization in which Calypte is engaged, and which are made by you, alone
or in combination with others, which result from or relate to the services you
perform for Calypte hereunder, and whether made on behalf of Calypte under this
Agreement, or with the use of or as a result of access to Confidential
Information, including but not limited to any derivative work which constitutes
an improvement or modification to any tangible form of Confidential Information,
as hereinafter defined, such as any design, drawing, or product that embodies
Confidential Information.

                            (ii)  "DESIGNS AND MATERIALS" means all designs,
discoveries, inventions, products, computer programs, procedures, improvements,
developments, drawings, notes, documents, information and materials made,
conceived or developed by you alone or with others which result from or relate
to the services you perform for Calypte hereunder.

                            (iii) "MORAL RIGHTS" means any right to claim
authorship of a work, any right to object to any distortion or other
modification of a work, and any similar right, existing under the law of any
country in the world, or under any treaty.

                  (b) ASSIGNMENT OF OWNERSHIP. You agree that all the
Inventions, Designs and Materials that (1) are developed using equipment,
supplies, facilities or trade secrets of Calypte, (2) result from work performed
by you for Calypte or (3) relate to Calypte's business or current or anticipated
research and development, will be the sole and exclusive property of Calypte.
You hereby irrevocably transfer and assign any and all of your right, title, and
interest in and to Inventions, Designs and Materials, including but not limited
to all patent rights, copyrights,


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David Collins
October 18, 1999
Page 6


trademarks and trade secrets, to Calypte. All Inventions, Designs and Materials
will be the sole property of Calypte and Calypte will have the sole right to
determine the treatment of any Inventions, Designs and Materials, including the
right to keep them as trade secrets, to file and execute patent applications on
them, to use and disclose them without prior patent application, to file
registrations for copyright or trademark on them in its own name, or to follow
any other procedure that Calypte deems appropriate. You acknowledge that
copyrightable works prepared by you within the scope of your service hereunder
are "works for hire" under the federal Copyright Act and that Calypte will be
considered the author thereof. If Calypte files an original United States patent
application covering any invention of which you are a named inventor, you will
receive in each case from Calypte an inventor's fee of One Hundred Dollars
$100.00 in cash as full compensation therefor. You will:

                            (i)   Disclose promptly in writing to Calypte all
Inventions, Designs and Materials; and

                            (ii)  Cooperate with and assist Calypte to apply
for, and to execute any applications and/or assignments reasonably necessary to
obtain, any patent, copyright, trademark or other statutory protection for
Inventions, Designs and Materials in Calypte's name as Calypte deems
appropriate, provided that Calypte will reimburse you for any reasonable costs
incurred by you, and your normal billing rate for reasonable time incurred, in
connection therewith; and

                            (iii) Otherwise treat all Inventions, Designs and
Materials as "Confidential Information," as defined below. Your obligations to
so disclose, assist, and execute will survive until the earlier of your death or
disability or five years following any expiration or termination of this
Agreement.

                  (c) MORAL RIGHTS WAIVER. You hereby irrevocably transfer and
assign to Calypte any and all Moral Rights that you may have in any services you
render hereunder, or in any Inventions, Designs and Materials or products of
Calypte. You also hereby forever waive and agree never to assert against
Calypte, its successors or licensees any and all Moral Rights you may have in
any such services, Inventions, Designs and Materials or such products, even
after expiration or termination of this Agreement.

                  (d) COMPANY PROPERTY. All papers, records, data, notes,
drawings, files, documents, samples, devices, products, equipment, and other
materials, including copies and in whatever form, relating to the business of
Calypte that you possess or create as a result of your service to Calypte,
whether or not confidential, are the sole and exclusive property of Calypte.

         6. CONFIDENTIAL INFORMATION. You acknowledge that you will acquire
information and materials from Calypte and knowledge about the business,
products, programming techniques, experimental work, customers, clients and
suppliers of Calypte and that all such knowledge, information and materials
acquired, the existence, terms and conditions of this Agreement, and the Designs
and Materials, are and will be the trade secrets and confidential and
proprietary information of Calypte (collectively "CONFIDENTIAL INFORMATION").
Confidential Information will


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David Collins
October 18, 1999
Page 7


not include, however, any information which is or becomes part of the public
domain through no fault of your own or that Calypte regularly gives to third
parties without restriction on use or disclosure. You will hold all such
Confidential Information in strict confidence, and will not disclose it to
others or use it in any way, commercially or otherwise, except in performing
your services hereunder, and will not allow any unauthorized person access to
it, either before or after expiration or termination of this Agreement. You will
take all action reasonably necessary and satisfactory to protect the
confidentiality of the Confidential Information in your possession, including,
without limitation, implementing and enforcing operating procedures to minimize
the possibility of unauthorized use or copying of the Confidential Information.

         7.       TERM OF SERVICE; TERMINATION; EFFECT OF TERMINATION.

                  (a) TERM OF SERVICE. This Agreement is for a period of twelve
(12) months from and after the Effective Date, subject to earlier termination as
provided in Section 7(b) hereof.

                  (b)      TERMINATION; EFFECT OF TERMINATION.

                            (i)   TERMINATION.  This Agreement will terminate
automatically upon the earliest of (A) your death, (B) such date as you
voluntary terminate service, by written notice to Calypte, or (C) the date upon
which Calypte terminates your service hereunder for cause by giving written
notice thereof to you, stating therein that such termination is for cause and
specifying in reasonable detail such cause, or (D) the date upon which your
successor as Chief Executive Officer of Calypte has been appointed as such by
the Board. For purposes of this Agreement, "cause" is defined as your willful
failure to follow lawful and commercially reasonable directives of the Board,
and/or intentional damage to the tangible or intangible property of Calypte,
and/or conviction of a crime involving moral turpitude, and/or the performance
of any dishonest or fraudulent act which is or would be, in each case as
determined in good faith by the Board, materially detrimental to the interest of
Calypte and its other stockholders.

                            (ii)  EFFECT OF TERMINATION. Upon termination of
your service with Calypte hereunder for any reason, Calypte will pay you all of
your accrued and unpaid expenses, if any, provided, as to a given expense, you
have submitted commercially customary support documentation to Calypte therefor.
If this Agreement is terminated for any reason other than your voluntary
termination hereof or termination Calypte for cause, and if you have rendered
less than five (5) days of service in the month during which this Agreement so
terminates, you will not be obligated to return any portion of the retainer
amount paid to you for such month. If this Agreement is terminated by you
voluntarily, or by Calypte for cause, during a month for which you already have
been paid the monthly retainer by Calypte, and at the time of such termination
you have rendered less than five (5) days of Services during such month, you
will, within thirty (30) days after the date of such termination, repay to
Calypte in cash an amount equal to at $1,000.00 times the number of days of
Services less than five that you did render in such month. Your obligations of
confidentiality hereunder will survive any such termination, and termination


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David Collins
October 18, 1999
Page 8


hereof will not have any effect on any other binding agreement between Calypte
and you except to the extent specifically so stated in such other agreement or
agreements. Your termination hereunder will not be deemed to be a termination of
all your services with Calypte, for purposes of your Option, if you then are
still serving Calypte as a consultant, including service as a Director.

         8. PRIOR CONTRACTS. You represent that except as disclosed in writing
to Calypte, (a) there are no other contracts to assign Inventions, Designs or
Materials that are, as of the Effective Date, in existence between you and any
other person or entity, and (b) as of the Effective Date, you have no
employment, consultancies or undertakings which would restrict or impair your
performance of this Agreement.

         9. GENERAL. This Agreement may be executed in counterparts, each of
which will be deemed an original, but both of which together will constitute one
and the same instrument. This Agreement will be governed by the laws of the
State of California without regard to its body of law controlling conflict of
laws. This Agreement is the complete and exclusive agreement between you and
Calypte regarding the specific subject matter of this Agreement, which subject
matter relates solely to your rendering of services to Calypte as a consultant
in the position of Chief Executive Officer of Calypte, and not to any other
binding agreement you may have with Calypte nor with respect to your service as
a Director of Calypte, and supersedes in their entirety all prior agreements,
understandings and communications, oral or written, between us regarding such
specific described subject matter. This Agreement will be binding upon and inure
to our respective successors and assigns, and upon your heirs, executors and
administrators, and may only be amended by a writing signed by each of us or our
respective successors, assigns or authorized representatives.

         We look forward to continuing to work with you, Dave, as part of our
team for the success of Calypte.

                                  Sincerely,

                                  /s/ WILLIAM BOEGER
                                  ----------------------------------
                                  William Boeger
                                  Chairman of the Board


ACCEPTED AND AGREED:

/s/ DAVID COLLINS
----------------------------------
        DAVID COLLINS
Date signed:  October 18, 1999