Exhibit 10.112

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CONVERTIBLE DEBENTURE PURCHASE AGREEMENT

Among

CALYPTE BIOMEDICAL CORPORATION

and

THE INVESTOR SIGNATORY HERETO

Dated as of ____________, 2002

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          CONVERTIBLE DEBENTURE PURCHASE AGREEMENT (this “Agreement”), dated as
of __________, among Calypte Biomedical Corporation, a Delaware corporation (the
“Company”), and the investor signatory hereto (the “Purchaser”).

          WHEREAS, subject to the terms and conditions set forth in this
Agreement in accordance with Section 4(2) of the Securities Act of 1933, as
amended (the “Securities Act”), the Company desires to issue and sell to the
Purchaser and the Purchaser, desires to purchase from the Company, a $_________
8% Convertible Debenture, due ___________, which shall be in the form of Exhibit
A (the “Debentures”), and which is convertible into shares of the Company’s
common stock, $.001 par value per share (the “Common Stock”).

          NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in
this Agreement, and for other good and valuable consideration the receipt and
adequacy of which are hereby acknowledged, the Company and the Purchasers agree
as follows:

ARTICLE I
PURCHASE AND SALE

          1.1     The Closing

                    (a)     The Closing.     Subject to the terms and conditions
set forth in this Agreement, the Company shall issue and sell to the Purchaser
and the Purchaser shall purchase from the Company the Debenture for a purchase
price of $________ immediately following the execution hereof or such later date
as the parties shall agree. The date of the Closing is hereinafter referred to
as the “Closing Date.”

                              (ii)     At the Closing, the parties shall deliver
or shall cause to be delivered the following: (A) the Company shall deliver to
Purchaser: (A) Debenture registered in the name of such Purchaser in the
aggregate principal amount indicated below the Purchaser’s name on the signature
page to this Agreement, and (B) The Purchaser will deliver to the Company: (1)
the purchase price indicated below such Purchaser’s name on the signature page
to this Agreement in United States dollars in immediately available funds by
wire transfer to an account designated in writing by the Company for such
purpose, and (2) an executed Debenture Purchase Agreement.

          1.2     Certain Defined Terms.  For purposes of this Agreement,
“Conversion Price,” “Original Issue Date” and “Trading Day” shall have the
meanings set forth in the Debentures; “Business Day” shall mean any day except
Saturday, Sunday and any day which shall be a federal legal holiday in the
United States or a day on which banking institutions in the States of New York
or California are authorized or required by law or other governmental action to
close; A “Person” means an individual or corporation, partnership, trust,
incorporated or unincorporated association, joint venture, limited liability
company, joint stock company, government (or an agency or subdivision thereof)
or other entity of any kind.

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ARTICLE II
REPRESENTATIONS AND WARRANTIES

          2.1     Representations and Warranties of the Company. The Company
hereby makes the following representations and warranties to the Purchasers:

                    (a)     Organization and Qualification. The Company is a
corporation duly incorporated, validly existing and in good standing under the
laws of the State of Delaware with the requisite corporate power and authority
to own and use its properties and assets and to carry on its business as
currently conducted. The Company is duly qualified to do business and is in good
standing as a foreign corporation or other entity in each jurisdiction in which
the nature of the business conducted or property owned by it makes such
qualification necessary, except where the failure to be so qualified or in good
standing, as the case may be, could not, individually or in the aggregate, (x)
adversely affect the legality, validity or enforceability of the Securities (as
defined below) or any of this Agreement, or the Debenture (collectively, the
“Transaction Documents”), (y) have or result in a material adverse effect on the
results of operations, assets, prospects, or condition (financial or otherwise)
of the Company, taken as a whole, or (z) adversely impair the Company’s ability
to perform fully on a timely basis its obligations under any of the Transaction
Documents (any of (x), (y) or (z), a “Material Adverse Effect”).

                    (b)     Authorization; Enforcement. The Company has the
requisite corporate power and authority to enter into and to consummate the
transactions contemplated by each of the Transaction Documents and otherwise to
carry out its obligations thereunder. The execution and delivery of each of the
Transaction Documents by the Company and the consummation by it of the
transactions contemplated thereby have been duly authorized by all necessary
action on the part of the Company and no further action is required by the
Company. Each of the Transaction Documents has been duly executed by the Company
and, when delivered in accordance with the terms hereof, will constitute the
valid and binding obligation of the Company enforceable against the Company in
accordance with its terms. The Company is not in violation of any of the
provisions of its certificate or articles of incorporation, by-laws or other
organizational or charter documents.

                    (c)     Issuance of the Debenture. The Company will have
(and will, at all times while the Debenture is outstanding, maintain) an
adequate reserve of duly authorized shares of Common Stock, reserved for
issuance to the holder of such Debenture, to enable it to perform its
conversion, exercise and other obligations under this Agreement and, the
Debenture. Such number of reserved and available shares of Common Stock shall
not be less than the sum of 100% of the number of shares of Common Stock which
would be issuable upon conversion in full of the Debentures assuming such
conversion occurred on the Original Issue Date of the Debenture remain
outstanding for one year and all interest is paid in shares of Common Stock
(“initial minimum”). All such authorized shares of Common Stock shall be duly
reserved for issuance to the holder of the Debenture. The shares of Common Stock
issuable upon conversion of the Debenture are collectively referred to herein as
the “Underlying Shares.” The Debenture, and the Underlying Shares are
collectively referred to herein as, the “Securities.” When issued in accordance
with the Debenture, the Underlying Shares will be duly authorized, validly
issued, fully paid and nonassessable, free and clear of all liens, encumbrances
and rights of first refusal of any kind (collectively, “Liens”).

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                    (d)     No Conflicts. The execution, delivery and
performance of the Transaction Documents by the Company and the consummation by
the Company of the transactions contemplated thereby do not and will not (i)
conflict with or violate any provision of the Company’s certificate or articles
of incorporation, bylaws or other charter documents (each as amended through the
date hereof), or (ii) result in a violation of any law, rule, regulation, order,
judgment, injunction, decree or other restriction of any court or governmental
authority to which the Company is subject (including federal and state
securities laws and regulations), or by which any property or asset of the
Company is bound or affected; except in the case of clause (ii), as could not,
individually or in the aggregate, have or result in a Material Adverse Effect.
The business of the Company is not being conducted in violation of any law,
ordinance or regulation of any governmental authority, except for violations
which, individually or in the aggregate, could not have or result in a Material
Adverse Effect.

                    (e)     Filings, Consents and Approvals. The Company is not
required to obtain any consent, waiver, authorization or order of, give any
notice to, or make any filing or registration with, any court or other federal,
state, local or other governmental authority in connection with the execution,
delivery and performance by the Company of the Transaction Documents, other than
(i) the filings required pursuant to Section 3.10, (ii) the filing with the
Securities and Exchange Commission (the “Commission”) of a registration
statement covering the resale of the Underlying Shares by the Purchasers (the
“Underlying Shares Registration Statement”), (iii) the application(s) if
applicable to the Nasdaq SmallCap Market (“NASDAQ”) for the listing of the
Underlying Shares for trading on the NASDAQ (and with any other national
securities exchange or market on which the Common Stock is then listed) in the
time and manner required thereby, (iv) applicable Blue Sky filings, and (v) in
all other cases where the failure to obtain such consent, waiver, authorization
or order, or to give such notice or make such filing or registration could not
have or result in, individually or in the aggregate, a Material Adverse Effect
(collectively, the “Required Approvals”).

                    (f)     Litigation; Proceedings. There is no action, suit,
inquiry, notice of violation, proceeding or investigation pending or, to the
knowledge of the Company, threatened against or affecting the Company or any of
its Subsidiaries or any of their respective properties before or by any court,
arbitrator, governmental or administrative agency or regulatory authority
(federal, state, county, local or foreign) (collectively, an “Action”) which
adversely affects or challenges the legality, validity or enforceability of any
of the Transaction Documents or the Securities. The Company is not currently nor
has it been the subject of any Action involving a claim of violation of or
liability under federal or state securities laws or a claim of breach of
fiduciary duty. The Company does not have pending before the Commission any
request for confidential treatment of information. There has not been, and to
the best of the Company’s knowledge there is not pending or contemplated, any
investigation by the Commission involving the Company.

                    (g)     Private Offering. Assuming the accuracy of the
representations and warranties of the Purchaser set forth in Sections
2.2(b)-(g), the offer, issuance and sale of the Securities to the Purchaser as
contemplated hereby are exempt from the registration requirements of the
Securities Act. Neither the Company nor any Person acting on its behalf has
taken or is, to the knowledge of the Company, contemplating taking any action
which could subject the offering, issuance or sale of the Securities to the
registration requirements of the Securities Act including soliciting any offer
to buy or sell the Securities by means of any form of general solicitation or
advertising.

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                    (h)     SEC Documents; Financial Statements. The Company has
filed all reports required to be filed by it under the Securities Exchange Act
of 1934, as amended (the “Exchange Act”), including, without limitation, all
filings required pursuant to Sections 13(a) and 15(d) thereof, for the two years
preceding the date hereof (or such shorter period as the Company was required by
law to file such material) (the foregoing materials being collectively referred
to herein as the “SEC Documents” or the “Disclosure Materials”) on a timely
basis or has received a valid extension of such time of filing and has filed any
such SEC Documents prior to the expiration of any such extension. The financial
statements of the Company included in the SEC Documents comply in all material
respects with applicable accounting requirements and the rules and regulations
of the Commission with respect thereto as in effect at the time of filing. Such
financial statements have been prepared in accordance with generally accepted
accounting principles applied on a consistent basis during the periods involved
(“GAAP”), except as may be otherwise specified in such financial statements or
the notes thereto, and fairly present in all material respects the financial
position of the Company as of and for the dates thereof and the results of
operations and cash flows for the periods then ended, subject, in the case of
unaudited statements, to normal, immaterial, year-end audit adjustments.

                    (i)     Investment Company. The Company is not, and is not
an Affiliate (as defined in Rule 405 under the Securities Act) of, an
“investment company” within the meaning of the Investment Company Act of 1940,
as amended.

                    (j)     Certain Fees. Except for certain fees payable to LTF
LLC by the Company, no fees or commissions will be payable by the Company to any
broker, financial advisor or consultant, finder, placement agent, investment
banker, bank or other Person with respect to the transactions contemplated by
this Agreement. The Purchaser shall have no obligation with respect to any fees
or with respect to any claims made by or on behalf of other Persons for fees of
a type contemplated in this Section that may be due in connection with the
transactions contemplated by this Agreement. The Company shall indemnify and
hold harmless the Purchaser, from and against all claims, losses, damages, costs
and expenses suffered in respect of any such claimed or existing fees, as such
fees and expenses are incurred.

                    (k)     Solicitation Materials. Neither the Company nor any
Person acting on the Company’s behalf has solicited any offer to buy or sell the
Securities by means of any form of general solicitation or advertising.

                    (l)     Patents and Trademarks. The Company and its
Subsidiaries have, or have rights to use, all patents, patent applications,
trademarks, trademark applications, service marks, trade names, copyrights,
licenses and rights which are necessary or material for use in connection with
their respective businesses as described in the SEC Documents and which the
failure to so have would have a Material Adverse Effect (collectively, the
“Intellectual Property Rights”). Neither the Company nor any Subsidiary has
received a written notice that the Intellectual Property Rights used by the
Company or its Subsidiaries violates or infringes upon the rights of any Person.
To the best knowledge of the Company, all such Intellectual Property Rights are
enforceable and there is no existing infringement by another Person of any of
the Intellectual Property Rights.

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                    (m)     Registration Rights; Rights of Participation. The
Company grants to Purchaser “piggy-back” registration rights to have the
Securities registered with the Commission on a best efforts basis subject to any
pre-existing registration rights agreements the Company may have.

                    (n)     Regulatory Permits. The Company possess all
certificates, authorizations and permits issued by the appropriate federal,
state or foreign regulatory authorities necessary to conduct their respective
businesses as described in the SEC Documents, except where the failure to
possess such permits could not, individually or in the aggregate, have or result
in a Material Adverse Effect (“Material Permits”), and neither the Company nor
any such Subsidiary has received any notice of

                    (o)     proceedings relating to the revocation or
modification of any Material Permit.

                    (p)     Labor Relations. No material labor problem exists
or, to the knowledge of the Company, is imminent with respect to any of the
employees of the Company.

                    (q)     Disclosure. The Company confirms that neither it nor
any other Person acting on its behalf has provided any of the Purchasers or its
agents or counsel with any information that constitutes or might constitute
material non-public information.

          2.2     Representations and Warranties of the Purchasers. The
Purchaser hereby for itself and for no other Purchaser represents and warrants
to the Company as follows:

                    (a)     Investment Intent. Purchaser is acquiring the
Securities as principal for its own account for investment purposes only and not
with a view to or for distributing or reselling such Securities or any part
thereof, without prejudice, however, to such Purchaser’s right, subject to the
provisions of this Agreement, the Debenture at all times to sell or otherwise
dispose of all or any part of such Securities pursuant to an effective
registration statement under the Securities Act or under an exemption from such
registration and in compliance with applicable federal and state securities
laws. Nothing contained herein shall be deemed a representation or warranty by
such Purchaser to hold the Securities for any period of time. Purchaser is
acquiring the Securities hereunder in ordinary course. Purchaser does not have
any agreement or understanding, directly or indirectly, with any Person to
distribute the Securities.

                    (b)     Purchaser Status. At the time Purchaser was offered
the Securities, it was, and at the date hereof it is an “accredited investor” as
defined in Rule 501(a) under the Securities Act.

                    (c)     Experience of such Purchaser. Purchaser, either
alone or together with its representatives, has such knowledge, sophistication
and experience in business and financial matters so as to be capable of
evaluating the merits and risks of the prospective investment in the Securities,
and has so evaluated the merits and risks of such investment.

                    (d)     Ability of such Purchaser to Bear Risk of
Investment. Purchaser is able to bear the economic risk of an investment in the
Securities and, at the present time, is able to afford a complete loss of such
investment.

                    (e)     Access to Information. Purchaser acknowledges that
it has reviewed the Disclosure Materials and has been afforded (i) the
opportunity to ask such questions as it has deemed necessary of, and to receive
answers from, representatives of the Company concerning the terms and

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conditions of the offering of the Securities and the merits and risks of
investing in the Securities; (ii) access to information about the Company and
the Company’s financial condition, results of operations, business, properties,
management and prospects sufficient to enable it to evaluate its investment; and
(iii) the opportunity to obtain such additional information which the Company
possesses or can acquire without unreasonable effort or expense that is
necessary to make an informed investment decision with respect to the investment
and to verify the accuracy and completeness of the information contained in the
Disclosure Materials.

                    (f)     General Solicitation. Purchaser is not purchasing
the Securities as a result of or subsequent to any advertisement, article,
notice or other communication regarding the Securities published in any
newspaper, magazine or similar media or broadcast over television or radio or
presented at any seminar or any other general solicitation or general
advertisement.

                    (g)     Reliance. Purchaser understands and acknowledges
that (i) the Securities are being offered and sold to it without registration
under the Securities Act and (ii) the availability of such exemption, depends in
part on, and the Company will rely upon the accuracy and truthfulness of, the
foregoing representations and Purchaser hereby consents to such reliance.

                    (h)     Integration.    Purchaser acknowledges that in the
event the registration of or the offering is subject to an integration issue
raised by the Commission, Purchaser will hold Company harmless for any claims.

                    (j)     Opportunity to Review.     Purchaser represents to
Company, that Purchaser has been afforded ample opportunity to review the terms
of this transaction with legal and/or financial advisors of Purchaser’s choice.
Additionally, Purchaser has been afforded an opportunity to ask questions of
Company related to the Company’s commission filings and/or the Transaction
Document.

ARTICLE III
OTHER AGREEMENTS OF THE PARTIES

          3.1     Transfer Restrictions. (a) Securities may only be disposed of
pursuant to an effective registration statement under the Securities Act, to the
Company or pursuant to an available exemption from or in a transaction not
subject to the registration requirements of the Securities Act, and in
compliance with any applicable federal and state securities laws. In connection
with any transfer of Securities other than pursuant to an effective registration
statement or to the Company, except as otherwise set forth herein, the Company
may require the transferor thereof to provide to the Company an opinion of
counsel selected by the transferor, the form and substance of which opinion
shall be reasonably satisfactory to the Company, to the effect that such
transfer does not require registration of such transferred securities under the
Securities Act.

                    (b)     The Purchaser agrees to the imprinting, so long as
is required by this Section 3.1(b), of the following legend on the Securities:

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                      NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH
THESE SECURITIES ARE [CONVERTIBLE] HAVE BEEN REGISTERED WITH THE SECURITIES AND
EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON
AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
“SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT
TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO
AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH
APPLICABLE STATE SECURITIES LAWS, AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO
THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY
ACCEPTABLE TO THE COMPANY.

                              Underlying Shares shall not contain the legend set
forth above nor any other legend if the conversion of the Debenture occurs at
any time while an Underlying Shares Registration Statement is effective under
the Securities Act or the holder of any such security is relying on Rule 144
promulgated under the Securities Act (“Rule 144”) in connection with the resale
of such Underlying Shares or in the event there is not an effective Underlying
Shares Registration Statement at such time and Rule 144 is not then available
if, in the opinion of counsel to the Company, such legend is not required under
applicable requirements of the Securities Act (including judicial
interpretations and pronouncements issued by the staff of the Commission). The
Company shall cause its counsel to issue a legal opinion as soon as practical
after the Underlying Shares Registration Statement is declared effective by the
Commission (the “Effective Date”). The Company agrees that in the event any
Underlying Shares are issued with a legend in accordance with this Section
3.1(b), it will use its best efforts, within seven (7) Trading Days after
request therefore by a Purchaser, provide such Purchaser with a certificate or
certificates representing such Underlying Shares, free from such legend at such
time as such legend would not have been required under this Section 3.1(b) had
such issuance occurred on the date of such request. The Company may not make any
notation on its records or give instructions to any transfer agent of the
Company which enlarge the restrictions of transfer set forth in this Section.

          3.2     Acknowledgment of Dilution. The Company acknowledges that the
issuance of the Underlying Shares upon the conversion of Debentures in
accordance with the terms of the Debentures, will result in dilution of the
outstanding shares of Common Stock.

          3.3     Furnishing of Information. As long as the Purchaser owns
Securities, the Company covenants use its best efforts to timely file (or obtain
extensions in respect thereof and file within the applicable grace period) all
reports required to be filed by the Company after the date hereof pursuant to
Section 13(a) or 15(d) of the Exchange Act. As long as the Purchasers own
Securities, if the Company is not required to file reports pursuant to such
sections, it will prepare and furnish to the Purchasers and make publicly
available in accordance with Rule 144(c) promulgated under the Securities Act
such information as is required for the Purchasers to sell the Securities under
Rule 144 promulgated under the Securities Act. The Company further covenants
that it will take such further action as any holder of Securities may reasonably
request, all to the extent required from time to time to enable such Person to
sell Underlying Shares without registration under the Securities Act within

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the limitation of the exemptions provided by Rule 144 promulgated under the
Securities Act, including causing its attorneys to render and deliver any legal
opinion required in order to permit a Purchaser to receive Underlying Shares
free of all restrictive legends and to subsequently sell Underlying Shares under
Rule 144 upon receipt of a notice of an intention to sell or other form of
notice having a similar effect. Upon the request of any such Person, the Company
shall deliver to such Person a written certification of a duly authorized
officer as to whether it has complied with such requirements.

          3.4     Conversion and Exercise Obligations of the Company. The
Company shall honor conversions of the Debentures and shall deliver Underlying
Shares in accordance with the terms, conditions and time periods set forth in
the Debenture.

          3.5     Certain Securities Laws Disclosures; Publicity. The Company
may: (i) on the Closing Date, issue a press release disclosing the transactions
contemplated hereby, (ii) file with the Commission a Report on Form 8-K
disclosing the transactions contemplated hereby, and (iii) file with the
Commission a Form D promulgated under the Securities Act.

          3.6     Use of Proceeds. The Company shall use the net proceeds from
the sale of the Securities hereunder for general working capital purposes
(including the payment of trade payables in the ordinary course of the Company’s
business and prior practices).

          3.7     Disclosure of Material Non-Public Information. The Company
shall not and shall cause each of its Affiliates and other Persons acting on
behalf of the Company not to divulge to any Purchaser any information that it
believes to be material non-public information unless such Purchaser has agreed
in writing to receive such information. The Company agrees to comply with newly
adopted Regulation FD, promulgated under the Exchange Act.

ARTICLE IV
MISCELLANEOUS

          4.1     Fees and Expenses. Each party shall pay the fees and expenses
of its advisers, counsel, accountants and other experts, if any, and all other
expenses incurred by such party incident to the negotiation, preparation,
execution, delivery and performance of this Agreement. The Company shall pay all
stamp and other taxes and duties levied in connection with the issuance of the
Securities

          4.2     Entire Agreement; Amendments. The Transaction Documents,
contain the entire understanding of the parties with respect to the subject
matter hereof and supersede all prior agreements and understandings, oral or
written, with respect to such matters, which the parties acknowledge have been
merged into such documents, exhibits and schedules.

          4.3     Notices. Any and all notices or other communications or
deliveries required or permitted to be provided hereunder shall be in writing
and shall be deemed given and effective on the earliest of (i) the date of
transmission, if such notice or

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communication is delivered via facsimile at the facsimile telephone number
specified in this Section prior to 6:30 p.m. (New York City time) on a Business
Day, (ii) the Business Day after the date of transmission, if such notice or
communication is delivered via facsimile at the facsimile telephone number
specified in this Agreement later than 6:30 p.m. (New York City time) on any
date and earlier than 11:59 p.m. (New York City time) on such date, (iii) the
Business Day following the date of mailing, if sent by U.S. nationally
recognized overnight courier service, or (iv) upon actual receipt by the party
to whom such notice is required to be given. The address for such notices and
communications shall be as follows:

  If to the Company:   Calypte Biomedical Corporation.
1265 Harbor Bay Parkway
Alameda, CA 94502
Facsimile No.: (510) 814-8494
Attn: Director of Finance           With copies to:   Baratta & Goldstein
597 Fifth Avenue
New York, NY 10017
Facsimile No.: (212) 750 8297
Attn: [Joseph Baratta]           If to a Purchaser:   To the address set forth
under such Purchaser’s name on the signature pages hereto.

or such other address as may be designated in writing hereafter, in the same
manner, by such Person.

          4.4     Amendments; Waivers. No provision of this Agreement may be
waived or amended except in a written instrument signed, in the case of an
amendment, by the Company and the Purchaser or, in the case of a waiver, by the
party against whom enforcement of any such waiver is sought. No waiver of any
default with respect to any provision, condition or requirement of this
Agreement shall be deemed to be a continuing waiver in the future or a waiver of
any other provision, condition or requirement hereof, nor shall any delay or
omission of either party to exercise any right hereunder in any manner impair
the exercise of any such right accruing to it thereafter.

          4.5     Headings. The headings herein are for convenience only, do not
constitute a part of this Agreement and shall not be deemed to limit or affect
any of the provisions hereof.

          4.6     Successors and Assigns. This Agreement shall be binding upon
and inure to the benefit of the parties and their successors and permitted
assigns. Except in the case of a merger or acquisition of the Company, the
Company may not assign this Agreement or any rights or obligations hereunder
without the prior written consent of the Purchaser. Except as set forth in
Section 3.1(a), the Purchasers may not assign this Agreement or any of the
rights or obligations hereunder without the consent of the Company. This
provision shall not limit any Purchaser’s right to transfer securities.

          4.7     No Third-Party Beneficiaries. This Agreement is intended for
the benefit of the parties hereto and their respective successors and permitted
assigns and is not for the benefit of, nor may any provision hereof be enforced
by, any other Person.

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          4.8     Governing Law.  All questions concerning the construction,
validity, enforcement and interpretation of this Agreement shall be governed by
and construed and enforced in accordance with the internal laws of the State of
New York, without regard to the principles of conflicts of law thereof. Each
party hereby irrevocably submits to the exclusive jurisdiction of the state and
federal courts sitting in the City of New York, borough of Manhattan, for the
adjudication of any dispute hereunder or in connection herewith or with any
transaction contemplated hereby or discussed herein (including with respect to
the enforcement of any of the Transaction Documents), and hereby irrevocably
waives, and agrees not to assert in any suit, action or proceeding, any claim
that it is not personally subject to the jurisdiction of any such court, that
such suit, action or proceeding is improper. Each party hereby irrevocably
waives personal service of process and consents to process being served in any
such suit, action or proceeding by mailing a copy thereof via registered or
certified mail or overnight delivery (with evidence of delivery) to such party
at the address in effect for notices to it under this Agreement and agrees that
such service shall constitute good and sufficient service of process and notice
thereof. Nothing contained herein shall be deemed to limit in any way any right
to serve process in any manner permitted by law.

          4.9     Survival.  The representations, warranties, agreements and
covenants contained herein shall survive the Closing and the delivery, exercise
or the Debentures.

          4.10   Execution.  This Agreement may be executed in two or more
counterparts, all of which when taken together shall be considered one and the
same agreement and shall become effective when counterparts have been signed by
each party and delivered to the other party, it being understood that both
parties need not sign the same counterpart. In the event that any signature is
delivered by facsimile transmission, such signature shall create a valid and
binding obligation of the party executing (or on whose behalf such signature is
executed) the same with the same force and effect as if such facsimile signature
page were an original thereof.

          4.11   Severability.  In case any one or more of the provisions of
this Agreement shall be invalid or unenforceable in any respect, the validity
and enforceability of the remaining terms and provisions of this Agreement shall
not in any way be affecting or impaired thereby and the parties will attempt to
agree upon a valid and enforceable provision which shall be a reasonable
substitute therefor, and upon so agreeing, shall incorporate such substitute
provision in this Agreement.

          4.12   Remedies.  In addition to being entitled to exercise all rights
provided herein or granted by law, including recovery of damages, each of the
Purchasers will be entitled to specific performance of the obligations of the
Company under the Transaction Documents. The parties hereto agree that monetary
damages may not be adequate compensation for any loss incurred by reason of any
breach of its obligations described in the foregoing sentence and hereby agrees
to waive in any action for specific performance of any such obligation the
defense that a remedy at law would be adequate.

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          IN WITNESS WHEREOF, the parties hereto have caused this Convertible
Debenture Purchase Agreement to be duly executed by their respective authorized
signatories as of the date first indicated above.

            CALYPTE BIOMEDICAL CORPORATION.

By:      _____________________________________
            Name:
            Title:

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FOLLOWS]

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  [                     ]

By:_____________________________________
     Name:       
     Title:

Purchase Price:              [  ]

Address for Notice:

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DEBENTURE

     THESE SECURITIES HAVE NOT BEEN REGISTERED WITH THE UNITED STATES SECURITIES
AND EXCHANGE COMMISSION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
“ACT”), OR THE SECURITIES COMMISSION OF ANY STATE UNDER ANY STATE SECURITIES
LAW. THEY ARE BEING OFFERED PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE
ACT. THE SECURITIES MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED IN THE
UNITED STATES OR TO U.S. PERSONS (AS SUCH TERM IS DEFINED) UNLESS THE SECURITIES
ARE REGISTERED UNDER THE ACT AND APPLICABLE STATE SECURITIES LAWS, OR SUCH
OFFERS, SALES AND TRANSFERS ARE MADE PURSUANT TO AVAILABLE EXEMPTIONS FROM THE
REGISTRATION REQUIREMENTS OF THE ACT AND THOSE LAWS.

     THESE SECURITIES HAVE NOT BEEN RECOMMENDED BY ANY FEDERAL OR STATE
SECURITIES COMMISSION OR REGULATORY AUTHORITY, ANY REPRESENTATION TO THE
CONTRARY IS A CRIMINAL OFFENSE.

                                                           $100,000 US

CALYPTE BIOMEDICAL CORPORATION

8% CONVERTIBLE DEBENTURE

     THIS DEBENTURE, issued this ____ day of June 2002, is a duly authorized
Debenture of Calypte Biomedical Corporation, a corporation duly organized and
existing under the law of the State of Delaware (the “Company”), designated as
its 8% Convertible Debenture Due June 17, 2003, in an aggregate principal amount
not exceeding $100,000 U.S. (the “Debenture”).

     FOR VALUE RECEIVED, the Company promises to pay to_________, the registered
holder hereof (the “Holder”), the principal sum of $100,000, on or prior to June
17, 2003, (the “Maturity Date”), and to pay interest on the principal sum
outstanding time to time on the last day of each June, September and December
and March(each an “Interest Payment Date”), commencing September 30, 2002, up to
and including the Maturity Date, at the rate of 8% per annum. Accrual of
interest on this Debenture shall commence on the date of this Debenture and
shall continue to accrue until the next Interest Payment Date. The interest so
payable will be paid on each Interest Payment Date to the person in whose name
this Debenture (or one or more predecessor Debenture) is registered on the
records of the Company regarding registration and transfers of the Debenture
(the “Debenture Register”) on the first business day prior to such Interest
Payment Date. All accrued and unpaid interest shall bear interest at the same
rate of 8% per annum from the date hereof until the date of payment. The
principal of this Debenture is payable in coin or currency of the United States
of America as at the time of payment is legal tender for public and private

15

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debts or, at the sole option of the Company, in shares of Common Stock under the
same conversion formula as stated in the within Debenture at the address of the
Holder last appearing on the Debenture Register of the Company as designated in
writing by the Holder from time to time. The Debenture Register shall represent
the record of ownership and right to receive principal and interest on this
Debenture. Interest and principal shall be payable only to the registered Holder
as reflected in the Debenture Register. At the Company’s sole option, interest
on the within Debenture will be payable in cash or shares of Common Stock under
the same conversion formula as stated in the within Debenture. The right to
receive principal and interest under this Debenture shall be transferable only
through an appropriate entry in the Debenture Register as provided herein. The
forwarding of such payment shall constitute a payment of interest hereunder and
shall satisfy and discharge the liability for principal and interest on this
Debenture to the extent of the sum represented by such payment. The Holder shall
have the exclusive right to demand payments of the principal (other than any
amount converted) in cash upon the due date, in the event of a default as
provided for herein prior to the due date.

      This Debenture is subject to the following additional provisions:

1.   Debenture.  The Debenture is exchangeable for an equal aggregate principal
amount of Debenture of different authorized denominations, as requested by the
Holder surrendering the same, but shall not be issuable in denominations less
than integral multiples of Fifty Thousand Dollars ($50,000 U.S.). No service
charge will be made for such registration of transfer or exchange.

2.   Withholding.  The Company shall be entitled to withhold if applicable from
all payments of interest on this Debenture, any amounts required to be withheld
under the applicable provisions of the United States income tax laws or other
applicable laws at the time of such payments if applicable. The Holder shall pay
all taxes, charges, or levies in connection with the issuance or transfer
thereof other than amounts so withheld.

3.   Transfer.  This Debenture has been issued subject to investment
representations of the original purchaser hereof and may be transferred or
exchanged only in compliance with the Securities Act of 1933, as amended (the
“Act”). Any Holder of this Debenture, by acceptance hereof, agrees to the
representations, warranties and covenants herein. Prior to due presentment to
the Company for transfer of this Debenture, the Company and any agent of the
Company may treat the person in whose name this Debenture is duly registered on
the Company’s Debenture Register as the owner hereof for the purpose of
receiving payment as herein provided and for all other purposes, whether or not
this Debenture be overdue, and neither the Company nor any such agent shall be
affected by notice to the contrary.

4.   Conversion.  The record Holders of this Debenture shall have conversion
rights as follows (the “Conversion Rights”):

      (a)   Right to Convert.  The record Holder of this Debenture shall be
entitled, at the option of the Holder, to convert any or all of the aggregate
principal amount of Debenture

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held by such Holder, at any time days after the date of issuance of this
Debenture, at the office of the Company or any transfer agent for the Debenture,
into that number of fully-paid and non-assessable shares of Common Stock of the
Company calculated in accordance with the following formula: Number of shares
issued upon conversion = Principal/Conversion Price, where

X Principal = The principal amount of the Debenture(s) to be converted,   X
Conversion Price = the product of (1) .70 times (2) either the last trading
price average or Closing Bid Price, as that term is defined below, of the
Company’s Common Stock for the five (5) trading days immediately preceding the
Date of Conversion, as defined below (the “Fixed Conversion Price”). For
purposes hereof, the term “Closing Bid Price” shall mean the closing bid price
of the Company’s Common Stock as reported by the OTCBB (or, if not reported by
OTCBB, as reported by such other exchange or market where traded). For purposes
hereof, there is a minimum conversion price of $.10.

      (b)     Mechanics of Conversion.  No fractional shares of Common Stock
shall be issued upon conversion of this Debenture. In lieu of any fractional
share to which the Holder would otherwise be entitled, the Company shall pay
cash to such Holder in an amount equal to such fraction multiplied by the
Conversion Price then in effect. In order to convert Debenture into full shares
of Common Stock, the Holder shall surrender the certificate or certificates
therefore, duly endorsed, by either overnight courier or 2-day courier, to the
office of the Company or of any transfer agent for the Debenture, and shall give
written notice to the Company at such office with a copy to President of
Company, tel 510-749-5100 facsimile 510-814-8494, that he elects to convert the
same, the number of Debenture so converted and a calculation of the number of
shares of Common Stock to be issued upon conversion (with an advance copy of the
certificate(s) and the notice by facsimile); provided, however, that the Company
shall not be obligated to issue certificates evidencing the shares of Common
Stock issuable upon such conversion unless either the certificates evidencing
such Debenture are delivered to the Company or its transfer agent as provided
above, or the Holder notifies the Company or its transfer agent that such
certificates have been lost, stolen or destroyed and executes an agreement
satisfactory to the Company to indemnify the Company from any loss incurred by
it in connection with such certificates. Notwithstanding the foregoing, the
conversion right of the Holder set forth herein shall be limited, solely to the
extent required, from time to time, such that in no instance shall the maximum
number of shares of Common Stock into which the Holder may convert this
Debenture exceed, at any one time, an amount equal to the remainder of (i) 4.99%
of the then issued and outstanding shares of Common Stock of the Company
following such conversion, minus (ii) the number of shares of Common Stock of
the Company then held by the Holder.

     The Company shall use its best efforts to issue and deliver to Holder or to
Holder=s Counsel (AHolder=s Counsel@) within seven (7) business days after
delivery to the Company of such certificates, or after such agreement and
indemnification, to such Holder

17

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of Debenture at the address of the Holder on the books of the Company, a
certificate or certificates for the number of shares of Common Stock with legend
to which the Holder shall be entitled as aforesaid. The date on which notice of
conversion is given (the “Date of Conversion”) shall be deemed to be the date in
such notice of conversion is received by the Company, provided that the original
Debenture to be converted are received by the transfer agent or the Company
within five business days thereafter and the person or persons entitled to
receive the shares of Common Stock issuable upon such conversion shall be
treated for all purposes as the record holder or holders of such shares of
Common Stock on such date. If the original Debenture to be converted are not
received by the transfer agent or the Company within five business days after
the Date of Conversion, the notice of conversion shall become null and void. In
the event of all said shares are not delivered as provided for herein, holder
may at its own option declare the within Debenture in default and demand
immediate payment of all principal and accrued interest.

     Following conversion of a Debenture, or a portion thereof, the principal
and, upon payment thereof of the interest owed on that Debenture or portion of
the Debenture so converted will be deemed paid in full and satisfied, and such
Debenture or portion thereof will no longer be outstanding.

     (c)     Reservation of Stock Issuable Upon Conversion.  The Company shall
at all times use its best efforts to reserve and keep available out of its
authorized but unissued shares of Common Stock, solely for the purpose of
effecting the conversion of the Debenture, such number of its shares of Common
Stock as shall from time to time be sufficient to effect the conversion of all
then outstanding Debenture; and if at any time the number of authorized but
unissued shares of Common Stock shall not be sufficient to effect the conversion
of all then outstanding Debenture, the Company will take such corporate action
as may be necessary to increase its authorized but unissued shares of Common
Stock to such number of shares as shall be sufficient for such purpose.

     (d)     Mandatory Payment or Conversion on Maturity Date.  Each Holder of a
Debenture outstanding on June 17, 2003, shall have the right to payment of all
principal on this Debenture paid to such Holder in cash or in immediately
available funds or at the sole option of the Company, in shares of Common Stock
computed in accordance with Section 4 above on June 17, 2003.

     (e)     Adjustment to Conversion Price.

              (i)  If prior to the conversion of all of the Debenture, the
number of outstanding shares of Common Stock is increased by a stock split,
stock dividend or other similar event, then the Fixed Conversion Price shall be
appropriately reduced. If, prior to conversion of all the Debenture, the number
of outstanding shares of Common Stock is decreased by a combination or
reclassification of shares, or other similar event, the Fixed Conversion Price
shall be appropriately increased.

              (ii)  If, prior to the conversion of all Debenture, there shall be
any merger, consolidation, exchange of shares, recapitalization, reorganization,
or other similar event, as

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a result of which shares of Common Stock of the Company shall be changed into
the same or a different number of shares of the same or another class or classes
of stock or securities of the Company or another entity, then the Holders of
Debenture shall thereafter have the right to purchase and receive upon
conversion of Debenture, upon the basis and upon the terms and conditions
specified herein and in lieu of the shares of Common Stock immediately
theretofore issuable upon conversion, such shares of stock and/or securities
which may be issued or payable with respect to or in exchange for the number of
shares of Common Stock immediately theretofore purchasable and receivable upon
the conversion of Debenture held by such Holders had such merger, consolidation,
exchange of shares, recapitalization or reorganization not taken place, and in
such case appropriate provisions shall be made with respect to the rights and
interests of the Holders of the Debenture to the end that the provisions hereof
(including, without limitation, provisions for adjustment of the Fixed
Conversion Price and of the number of shares issuable upon conversion of the
Debenture) shall thereafter be applicable, as nearly as may be practicable in
relation to any shares of stock or securities thereafter deliverable upon the
exercise hereof. The Company shall not effect any transaction described in this
subsection 4(e) unless the resulting successor or acquiring entity (if not the
Company) assumes by written instrument the obligation to deliver to the Holders
of the Debenture such shares of stock and/or securities as, in accordance with
the foregoing provisions, the Holders of the Debenture may be entitled to
purchase.

              (iv)  No adjustment need be made if it would result in a change of
less than 1% of the Conversion Price (whether the Fixed Conversion Price or the
Floating Conversion Price). Any adjustments required to be made by this
subsection shall be rounded up to the right to acquire the nearest whole number
of shares of Common Stock.

5.     Redemption.

       (a)  Right to Redeem on Conversion. The Company shall have the right,
after receipt of a notice of conversion pursuant to Section 4, to redeem in
whole or in part any Debenture submitted for conversion, immediately prior to
conversion. If the Company wishes to redeem some, but not all, of the Debenture
submitted for conversion, the Company shall notify the Holder on 5 days written
notice.

       (b)  Mechanics of Redemption on Conversion. The Company shall effect each
such redemption by giving notice of its election to redeem, by facsimile to
Holder or to Holder=s Counsel within 1 business day following receipt of a
notice of conversion from a Holder, with a copy by 2-day courier, to the Holder
of Debenture submitted for conversion at the address and facsimile number of
such Holder appearing in the Company’s register for the Debenture. Such
redemption notice shall indicate whether the Company will redeem all or part of
the Debenture submitted for conversion. The Company shall not be entitled to
send any notice of redemption and begin the redemption procedure unless it has
the full amount of the redemption price, in cash, available in a demand or other
immediately available account in a bank or similar financial institution on the
date the redemption notice is sent to shareholders.

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       The redemption price per Debenture shall equal the greater of (i) one
hundred and thirty percent (130%) multiplied by the then outstanding principal
amount plus unpaid interest to the date of redemption; or

(ii) [Principal + Interest] x Closing Bid Price on the Date of Conversion
                                        
                                Conversion Price

       For the purposes of the above formula, “Principal”, “Interest”, “Closing
Bid Price” and “Conversion Price” shall have the meanings set forth in Section
4(a).

       The redemption price shall be paid in cash to the Holder of Debenture
redeemed within 5 business days of the delivery of the notice of such redemption
to such Holder; provided, however, that the Company shall not be obligated to
deliver any portion of such redemption price unless either the certificates
evidencing the Debenture redeemed are delivered to the Company or its transfer
agent as provided in Section 4(b), or the Holder notifies the Company or its
transfer agent that such certificates have been lost, stolen or destroyed and
executes an agreement satisfactory to the Company to indemnify the Company from
any loss incurred by it in connection with such certificates.

                 (c)       No Other Redemption. The Company shall have no right
to redeem the Debenture except as provided in Section 5 hereof unless otherwise
agreed to by mutual written agreement between Company and Holder per Section 9
herein.

6.              No Prepayment. The Company shall have no right to prepay this
Debenture, in whole or in part, prior to the Maturity Date; provided, however,
that this Section 6 shall not prevent the Company from exercising the redemption
rights set forth in Section 5.

7.              No Impairment. Except as expressly provided herein, no provision
of this Debenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of, and interest on, this
Debenture at the time, place, and rate, and in the coin or currency, herein
prescribed. This Debenture and all other Debenture now and hereafter issued of
similar terms are direct obligations of the Company.

8.              Termination. After this Debenture shall have been surrendered
for conversion as herein provided or notice of conversion shall have been given
by the Company pursuant to Section 4(d) herein, this Debenture shall no longer
be deemed to be outstanding and all rights with respect to this Debenture,
including, without limitation, the right to receive interest hereon and the
principal hereof, shall forthwith terminate as of the Date of Conversion, except
only the right of the Holder hereof to receive shares of Common Stock in
exchange therefor.

9.              Protective Provisions. This Debenture may not be amended without
the prior written consent of the Holder hereof.

10.            Costs and Expenses. The Company agrees to pay all costs and
expenses, including reasonable attorney’s fees, which may be incurred by the
Holder in collecting any

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amount due under this Debenture.

11.              Events of Default; Remedies. If one or more of the following
described “Events of Default” shall occur:

       (a)       The Company shall default in the payment of principal or
interest on these Debenture: or

       (b)       Any of the representatives or warranties made by the Company
herein, in the Securities Subscription Agreement, dated as of the date hereof
relating to this Debenture (the “Subscription Agreement”) or in any certificate
or financial or other written statements heretofore or hereafter furnished by or
on behalf of the Company in connection with the execution and delivery of this
Debenture or the Subscription Agreement shall be false or misleading in a any
material respect at the time made; or

       (c)       The Company shall fail to perform or observe, in any material
respect, any other convenient term, provision, condition, agreement or
obligation of the Company under this Debenture and such failure shall continue
uncured for a period of fifteen (15) days after notice from Holder of such
failure; or

       (d)       The Company shall (1) become insolvent; (2) admit in writing
its inability to pay its debts generally as they mature; (3) make an assignment
for the benefit of creditors or commence proceedings for its dissolution; or (4)
apply for or consent to the appointment of a trustee, liquidator or receiver for
its or for a substantial part of its property or business; or

       (e)       A trustee, liquidator or receiver shall be appointed for the
Company or for a substantial part of its property or business without its
consent and shall not be discharged within thirty (30) days after such
appointment; or

       (f)        Any governmental agency or any court of competent jurisdiction
at the instance of any governmental agency shall assume custody or control of
the whole or any substantial portion of the properties or assets of the Company
and shall not be dismissed within thirty (30) days thereafter; or

       (g)       Any money judgment, writ or warrant of attachment, or similar
process in excess of Three Hundred Thousand Dollars ($300,000) shall be entered
or filed against the Company or any of its properties or other assets and shall
remain unpaid, unvacated, unbonded or unstayed for a period of fifteen (15) days
or in any event later than five (5) days prior to the date of any proposed sale
thereunder; or

       (h)       Bankruptcy, reorganization, insolvency or liquidation
proceedings or other proceedings for relief under any bankruptcy law or any law
for the relief of debtors shall be instituted by or against the Company and, if
instituted against the Company shall not be dismissed within thirty (30) days
after such instruction or if the Company shall by any action or answer approve
of, consent to, or acquiesce in any such proceedings or admit the

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material allegations of, or default in answering a petition filed in any
proceeding; or

       (i)       The Common Stock shall not be traded on an exchange or over the
counter market.

       Then, or at any time thereafter, and in each and every such case, unless
such Event or Default shall have been waived in writing by the Holder (which
waiver shall not be deemed to be a waiver of any subsequent default) at the
option of the Holder and in the Holder’s sole discretion, the Holder may
consider this Debenture immediately due and payable, without presentment, demand
protest or notice of any kind, all of which are hereby expressly waived,
anything herein or in any note or other instruments contained to the contrary
notwithstanding, and the Holder may immediately, and with expiration of any
period of grace, enforce any and all of the Holder’s rights and remedies
provided herein or any other rights or remedies afforded by law.

12.              Mergers Consolidations, etc. The Company shall not consolidate
or merge into, or transfer all or substantially all of its assets to, any
person, unless such person assumes the obligations of the Company under this
Debenture and immediately after such transaction no Event of Default exists. Any
reference of the Company shall refer to such surviving or transferee
corporation, and the obligations of the Company shall terminate upon such
assumption. If the Company merges or consolidates with another corporation or
sells or transfers all or substantially all of its assets to another person, and
the holders of the Common Shares are entitled to receive stock, securities or
property in respect of or in exchange for Common Shares, then as a condition of
such merger, consolidation, sale or transfer, either (i) the Company and any
such successor, purchaser or transferee shall amend this Debenture to provide
that it may thereafter be converted on the terms and subject to the conditions
set forth above into the kind and amount of stock, securities or property
receivable upon such merger, consolidation, sale or transfer by a holder of the
number of shares of Common Stock into which this Debenture might have been
converted immediately before such merger, consolidation, sale or transfer, or
(ii) if the Company is not the surviving entity in such merger, consolidation,
sale or transfer, the Company shall give the Holder at least thirty (30) days
prior written notice of the expected closing date of such transaction, and if
any portion of this Debenture has not been converted into Common Stock at the
election of the Holder prior to such closing, then the remaining principal
amount of this Debenture may, at the option of the Purchaser, be converted into
shares of Common Stock at the closing of such transaction. The Conversion Price
shall be the same as the applicable Conversion Price defined in Section 4 above.

13.              Lost or Destroyed Debenture. If this Debenture shall be
mutilated, lost, stolen or destroyed, the Company shall execute and deliver, in
exchange and substitution for and upon cancellation of a mutilated Debenture, or
in lieu of or in substitution for a lost, stolen or destroyed Debenture, a new
Debenture for the principal amount of this Debenture so mutilated, lost, stolen
or destroyed, but only upon receipt of evidence of such loss, theft or
destruction of such Debenture, and of the ownership thereof, and indemnity and
bond, if requested, all reasonably satisfactory to the Company.

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14.              Sales in Compliance with Applicable Law. Any Holder of this
Debenture, by acceptance hereof, agrees that such Holder will not offer, sell or
otherwise dispose of this Debenture of the shares of Common Stock issuable upon
exercise thereof except under circumstances which will not result in a violation
of the Act, promulgated under the Act, or any applicable state Blue Sky law or
similar laws relating to the sale of securities and the Holder agrees to provide
the Company with the documentation required by the Subscription Agreement
executed by the original Holder hereof to demonstrate that such offer, sale or
disposition complies with applicable securities laws.

15.              Governing Law. This Debenture shall be governed by and
construed in accordance with the laws of the State of New York, without giving
effect to the principles of conflicts of laws.

16.              Business Day Definition. For purposes hereof, the term
“business day” shall mean any day on which banks are generally open for business
in the State of New York, USA and excluding any Saturday and Sunday.

17.              Notices. Any notice, demand or request required or permitted to
be given by either the Company or the Holder pursuant to the terms of this
Agreement shall be in writing and shall be deemed given when delivered
personally, or by facsimile (with a hard copy to follow by two day courier),
addressed to the Company at 1265 Harbor Bay Parkway, Alameda, CA 94507 with a
copy to President, tel. 510-749-5100 facsimile 510-814-8494, or the Holder at
                          , or such other addresses as a party may request by
notifying the other in writing.

18.              Waiver. Any waiver by the Company or the Holder hereof of a
breach of any provision of this Debenture shall not operate as or be construed
to be a waiver of any breach of such provision or of any breach of any other
provision of this Debenture. The failure of the Company or the Holder hereof to
insist upon strict adherence to any term of this Debenture on one or more
occasions shall not be considered a waiver or deprive that party of the right
thereafter to insist upon strict adherence to that term or any other term of
this Debenture. Any waiver must be in writing.

19.              Unenforceable Provisions. If any provision of this Debenture is
invalid, illegal or unenforceable, the balance of this Debenture shall remain in
effect, and if any provision is inapplicable to any person or circumstance, it
shall nevertheless remain applicable to all other persons and circumstances.

20.              Change of Control. In the event of any insolvency proceedings,
and any receivership, liquidation or other similar proceedings in connection
therewith, relative to the Company, and in the event of any proceedings for
voluntary or involuntary liquidation, dissolution or other winding-up of the
Company, whether or not involving insolvency, then the holders of Senior Debt
shall be entitled to receive payment in full of all principal, premiums,
interest fees and charges, including without limitation post-petition interest,
on all Senior Debt before the Holders of the Debenture are entitled to receive
any payment on account of principal or interest upon the Debenture an no claim
or proof of claim shall be

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filed with the Company by or non behalf of the Holders that shall assert any
right to receive any payments in respect to the Debenture, except subject to the
payment in full of the principal and interest on all of the Senior Debt then
outstanding.

       If funds or assets which would otherwise be available to make payments in
respect of the Debenture are instead paid or distributed to the holders of
Senior Debt on account of the subordination provisions of this Section 22, the
Holders of the Debenture shall be subrogated to the rights of the holders of
Senior Debt to receive payments or distributions of assets of the Company
applicable to the Senior Debt.

       No action which the holders of the Senior Debt, or the Company with the
consent of the holders of the Senior Debt, may take or refrain from taking with
respect to any Senior Debt, or any bond, debenture, note or other similar
instrument or agreement representing the same, or any collateral therefor,
including a waiver or release thereof, or any agreement or agreements in
connection therewith, shall affect the subordination of the Debenture to the
Senior Debt. The subordination of the Debenture to the Senior Debt shall be
unconditional, notwithstanding any defect in the genuineness, validity,
regularity, or enforceability of the bonds, Debenture, notes, or other similar
instruments or agreements evidencing the Senior Debt or any other circumstances,
whether or not referred to herein, which might otherwise constitute a legal or
equitable discharge or a defense of the Holder. By it acceptance of the
Debenture, the Holders agree to execute and deliver such documents as may be
reasonably requested from time to time by the Company or the holder of any
Senior Debt in order to implement this Section 20.

21.       Enforcement Actions. The Holder of the Debenture agrees not to
commence any enforcement action as to the Debenture and the security interest
securing such indebtedness unless and until it has notified the Agent (as
defined in the Security Agreement) in writing of its intention to do so and a
period after the giving of such notice shall have elapsed, ending on the earlier
of the thirtieth (30th) day after the giving of such notice or the date of the
commencement of an insolvency proceeding as to the Company. During such period,
the Agent, acting on behalf of the Lenders (as defined in the Security
Agreement) shall have the right, but not the obligation, to cure any defaults
giving rise to such enforcement action.

22.       Amendment. The above Sections 20 and 21 may not be amended, or any of
their provisions waived, without the prior written consent of the Agent or each
of the holders of Senior Debt.

            IN WITNESS WHEREOF, the Company has caused this Debenture to be duly
executed by an officer thereof duly authorized.

  Calypte Biomedical Corporation.

By:
Name:
Title:

24

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EXHIBIT A

NOTICE OF CONVERSION

(To be Executed by the Registered Holder

in order to Convert the Debenture)

The undersigned hereby irrevocably elects to convert the above Debenture No.
_________ into shares of Common Stock, $.001 par value (the “Common Stock”), of
Calypte Biomedical Corporation (the “Company”) according to the conditions
hereof, as of the date written below. If shares are to be issued in the name of
a person other than undersigned, the undersigned will pay all transfer taxes
payable with respect thereto and is delivering herewith such certificates,
opinions, and signature guarantees as reasonably requested by the Company or its
Transfer Agent. No fee will be charged to the Holder for any conversion, except
for transfer taxes, if any.

The undersigned represents as follows:

       1.       The undersigned is not a Adealer@, as such term is defined in
Section 2(12) of the Act, or a person receiving a selling concession, fee or
otherwise remuneration in respect of the Shares.

       2.       The undersigned did not acquire the Shares with the intent to
evade the registration provisions of the Act or any Rule or Regulation of the
Untied States securities laws and will not offer or sell the Shares except in
compliance with the provisions of the Act. If this Debenture is being converted
during the Restricted Period (as that term is defined in the subscription
agreement executed by the original purchaser of this Debenture), the undersigned
represents that it is not a U.S. Person as defined in Regulation S promulgated
under the United States Securities Act of 1933, as amended (the “Act”) and is
not converting the Debenture on behalf of any U.S. Person. The undersigned also
represents and warrants that all offers and sales by the undersigned of the
shares of Common Stock issuable to the undersigned upon conversion of the
Debenture shall be made in compliance with Regulation S, pursuant to
registration of the Common Stock under the Act or pursuant to an exemption from
registration under the Act.

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Conversion calculations:     Date of Conversion

Applicable Conversion Price

Signature

Name

Address:

* The original Debenture and Notice of Conversion must be received by the
Company’s Transfer Agent before any shares of Common Stock will be issued. If
the original of this Debenture is not received by the Transfer Agent (or such
other person as the Company may specify) within five business days after the
date of conversion specified above, this notice of conversion shall become null
and void.

Signature Guaranteed:      _______________________

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