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                                                                  Exhibit 10.70

                             DISTRIBUTION AGREEMENT

         THIS AGREEMENT is made this 11th day of May, 2000, by and between
Calypte Biomedical Corporation ("Calypte"), incorporated under the laws of
Delaware, and Biobras S.A. ("DISTRIBUTOR"), incorporated under the laws of
Brazil.

WHEREAS, Calypte is a developer and manufacturer of in vitro diagnostic kits
and kit components, and whereas DISTRIBUTOR wishes to commercially distribute
said kits and kit components in its Territory;

WHEREAS, in consideration of the mutual covenants and promises set forth
below, and with intent to be legally bound, the parties agree as follows:

ARTICLE 1 - DEFINITIONS
         (A) "Product" shall mean the products listed in Schedule 1 hereof.

         (B) "Territory" shall mean Brazil.

         (C) "Exclusive Distributor" shall mean that no other distributor,
             regardless of location of principal offices shall have any rights
             to commercially distribute the Products for sale in the Territory.

         (D) "Trademarks" shall mean those commercial marks listed in Schedule
             4 hereof.

ARTICLE 2 - APPOINTMENT OF DISTRIBUTOR
2.0      APPOINTMENT Calypte hereby designates and appoints DISTRIBUTOR as its
         Exclusive Distributor in the Territory for the sale, promotion,
         support, and distribution of the urine HIV-1 Products in the
         Territory, and non-exclusive distributor for the serum HIV-1 and HTLV
         Products in the Territory, subject to the terms and conditions of this
         Agreement.

2.1      INDEPENDENT CONTRACTOR Except for the limited purpose set forth
         herein, nothing in this Agreement shall be deemed to constitute a
         partnership between the parties hereto or be deemed to constitute
         DISTRIBUTOR as agent or employee for Calypte for any purpose,
         including the right to contract in the name of or for the account of
         Calypte nor to assume or create any liability or obligation of any
         kind, express or implied, on behalf of Calypte in any way or for any
         purpose. This Agreement does not constitute a Trademark license or
         grant of Trademark rights. The relationship between the parties is
         that of independent contractors in which Calypte is the vendor and
         DISTRIBUTOR is the vendee.

ARTICLE 3   TERM
3.0      EFFECTIVE DATE This Agreement shall become effective as of the date
         first shown in this Agreement.

3.1      TERM Unless sooner terminated or unless renewed as provided herein,
         this Agreement shall terminate three years after the date upon which
         both the urine HIV-1 EIA and Western Blot tests are registered by the
         Brazilian authorities.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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3.2      EXTENSION Unless sooner terminated or otherwise renewed as provided
         herein, DISTRIBUTOR shall have the right to renew this Agreement for
         an additional two (2) year period provided: i) DISTRIBUTOR meets or
         exceeds the sales minima detailed in Schedule 3, and ii) DISTRIBUTOR
         notifies Calypte in writing of its intention to renew the Agreement no
         less than ninety (90) days prior to the date the Agreement would
         otherwise terminate, and iii) DISTRIBUTOR has not declined
         distribution rights for any new Product which Calypte has offered to
         DISTRIBUTOR during the term of the Agreement, provided the new
         Products offered to DISTRIBUTOR are Products which DISTRIBUTOR could
         be reasonably expected to sell.

ARTICLE 4   DISTRIBUTOR'S UNDERTAKINGS
         DISTRIBUTOR agrees, at its sole expense (unless otherwise expressly
         provided herein), during the term of this Agreement:

4.1.1    BEST EFFORTS At all times to use its best efforts to vigorously and
         actively market, advertise, promote, and extend the sale of the
         Products throughout the Territory. To this end, DISTRIBUTOR agrees to
         maintain an adequate and competent staff of sales and technical
         support personnel which can function in all languages of the
         Territory. All advertisements, brochures, and other materials
         distributed in connection with the sale of the Products shall be
         submitted to Calypte for prior written approval, such approval not to
         be unreasonably withheld.

4.1.2    TECHNICAL SUPPORT AND RECALL CAPABILITY To provide to Calypte's
         Technical Services department a monthly report detailing any customer
         complaint(s) related to performance of the Products, such report to be
         issued even in the absence of complaints during the reporting period.
         Complaint reports shall provide full particulars regarding the nature
         of the complaint(s) and mechanism(s) of successful resolution.
         DISTRIBUTOR also certifies that it has, and shall maintain, the
         capability of tracking Product shipments by lot number in order to
         facilitate a Product recall should such a recall be required.

4.1.3    MINIMA [*]

4.2      EXCLUSIVE TERRITORY Not to solicit customers for any of the Products
         outside the Territory, either directly or through any third party,
         without Calypte's prior written approval. Furthermore, should it
         become evident that Product sold by DISTRIBUTOR within the Territory
         is being resold outside the Territory by any customer of DISTRIBUTOR,
         to take such action as may be necessary to discontinue that practice.

4.3.1    REGISTRATION AND PERMITS At no charge to Calypte, to provide
         reasonable assistance to Calypte in the registration of the Products
         with the regulatory authorities in the Territory, and to provide
         reasonable assistance in securing such licenses and registrations
         which may be required in connection with the importation and sale of
         the Products in the Territory. Such assistance may include among
         others DISTRIBUTOR providing to Calypte, or directly to

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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         authorities, such information as may be necessary to permit the
         importation of Product or components, occasional communication with
         regulatory authorities, and the coordination of Product regulatory
         trials. Such trials may require DISTRIBUTOR to provide
         instrumentation, laboratory disposables, and the training and
         monitoring of trial sites. Calypte shall offer such guidance and test
         kits as may be required, provided that the requirement for test kits
         not exceed that required by the USFDA, plus payment of government
         registration fees and trial site fees directly associated with local
         registration of the Products.

4.3.2    Local law demands that Product registrations be held and administered
         by a local entity. Calypte hereby appoints DISTRIBUTOR for this
         purpose. DISTRIBUTOR shall at all times administer the registration(s)
         in accordance with Calypte's instruction. DISTRIBUTOR hereby certifies
         that in the event that this agreement is terminated for any reason by
         either party, DISTRIBUTOR shall not obstruct or challenge in any
         manner whatsoever the prompt and orderly transfer of Product
         registration(s) to another distributor, nor shall DISTRIBUTOR
         obstruct or challenge in any manner the re-registration of the
         Products by another distributor as the case may be.

4.4.1    ROLLING DEMAND PURCHASE FORECAST On a quarterly basis, and no later
         than the first Monday of the calendar quarter, to provide to Calypte a
         six-month rolling purchase forecast, the first three months of which
         shall be considered firm orders.

4.4.2    SALES REPORTS To submit to Calypte within thirty days of January 1 and
         July 1of each year a written summary as to the prevailing market
         conditions, the attitudes of customers, the activities of competitors,
         or any other market conditions which may significantly impact the
         sales of the Products in the Territory.

4.5.1    HANDLING OF PRODUCTS To ensure that the Products are handled, stored,
         and shipped in accordance with Calypte's instructions.

4.5.2    To order, and to maintain a representative selection of Calypte's
         up-to-date sales literature or other promotional material in good
         condition.

4.5.3    To maintain such stock of the Products as is reasonably necessary to
         enable DISTRIBUTOR to comply with its obligations hereunder.

4.6      SALES LEADS To exercise its best judgement to follow up on sales leads
         supplied by Calypte.

4.7      CONFIDENTIALITY Not at any time to divulge to any third party any
         Confidential Information relating to the Products or to Calypte's
         affairs or business or method of carrying on business, except so far
         as is necessary, to those authorized to have access to such
         information within DISTRIBUTOR's organization.

         DISTRIBUTOR may receive information from Calypte, its personnel, or
         through DISTRIBUTOR's activities under this Agreement, either by
         direct or indirect communication or observation; more specifically,
         Calypte will make available to DISTRIBUTOR, after execution of this
         Agreement, such marketing and quality control data, and other
         proprietary, secret, and confidential information owned by

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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         Calypte which, in the opinion of Calypte, are necessary for
         DISTRIBUTOR to sell the Products (herein collectively referred to as
         "Confidential Information").

         DISTRIBUTOR shall not make use of the Confidential Information other
         than in connection with the marketing and sale of the Products under
         this Agreement and shall under no circumstances disclose the
         Confidential Information to any third party. Except for such of the
         Confidential Information that becomes publicly available through
         Calypte or independent third parties, DISTRIBUTOR shall not use,
         employ or exploit the Confidential Information, except for the direct
         benefit of Calypte, without Calypte's written consent for the term of
         this Agreement and seven (7) years thereafter.

4.8      SUB-DISTRIBUTORS In the event that DISTRIBUTOR appoints
         subdistributors, such appointments shall be made only in the name and
         for the account of DISTRIBUTOR, shall be for a term no longer than the
         term of this Agreement, and shall not confer upon such subdistributors
         and/or independent sales representatives any rights greater than those
         which are granted by Calypte to DISTRIBUTOR under this Agreement.
         DISTRIBUTOR shall also impose on any such subdistributors and/or
         independent sales representatives the same obligations that Calypte
         has imposed on DISTRIBUTOR under this Agreement for the purpose of
         protecting the goodwill of Calypte and the Products.

4.9      LEGAL STANDARDS To advise Calypte in writing of any changes which
         DISTRIBUTOR becomes aware of in legal standards within the Territory
         pertaining to the Products during the term of this Agreement,
         including but not limited to packaging, labeling and ingredient
         standards, sufficiently in advance of the imposition of such legal
         standards as to permit Calypte's orderly scheduling and delivery of
         Product within DISTRIBUTOR's requested time of shipment.

4.10.1   LABELING To ensure that the Products are sold and promoted in the form
         and with the labeling or markings designated by Calypte, which shall
         be in accordance with local laws, and not to alter, remove, or
         interfere therewith without the prior written consent of Calypte.

4.10.2   DISTRIBUTOR LABELS Notwithstanding the generality of the foregoing,
         Calypte hereby authorizes DISTRIBUTOR to affix a small label which
         denotes DISTRIBUTOR as the authorized distributor in the Territory,
         such label to be applied in a manner which does not obscure Calypte's
         tradenames or other marks.

4.11.1   TRADEMARKS To respect Calypte's rights in connection with the Products
         (including but not limited to Calypte's patents, trademarks, and
         copyrights), to comply with all local laws and regulations with
         respect thereof, and to assist Calypte in taking any steps necessary
         to defend such rights. Any reasonable expenses incurred under this
         paragraph by DISTRIBUTOR, and which are preapproved by Calypte, shall
         be reimbursed by Calypte.

4.11.2   To acknowledge at all times Calypte's exclusive right, title, and
         interest in and to the trademarks associated with the Products listed
         in Schedule 1 and registered by Calypte in the United States of
         America or the Terrritory; and not at any time to do or cause to be
         done any act or any thing contesting or in any way impairing or
         tending to impair any part of such right, title and interest. In
         connection with any reference to the trademarks, DISTRIBUTOR shall
         not in any manner represent that it has ownership interest in the
         trademarks or registration thereof, but shall clearly indicate
         Calypte's ownership of the trademarks.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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4.11.3   To use no trademarks, trade names, corporate names, or trade styles
         employing the trademarks, whether in advertising or otherwise, without
         the prior written consent of Calypte, such consent not to be
         unreasonably withheld, and generally not to produce any advertising or
         promotional material or activity without Calypte's written consent.
         Except as provided in Article 9.1.3, any and all use by DISTRIBUTOR of
         said trademarks, trade names, corporate names or trade styles within
         the Territory shall cease upon the expiration or termination of this
         Agreement.

4.12     PRESS To make no statements to the press concerning Calypte's
         personnel, business practices, Product development efforts, or alleged
         Product performance problems without the prior written consent of
         Calypte.

4.13     MANAGEMENT CHANGE To provide to Calypte prompt notice, in writing, of
         any change of key management or ownership and any change in the mode
         of operation of DISTRIBUTOR.

4.14     PROOF OF SALE To expressly represent that any Products purchased are
         for the purpose of sale in the Territory and will furnish upon
         Calypte's requests, documents which certify that the Products have
         been sold in that Territory. DISTRIBUTOR further represents that it
         will undertake all appropriate steps to ensure that the Products are
         sold exclusively to customers which are permitted under the laws of
         the Territory to purchase and use the Products.

4.15     AUDIT To permit Calypte staff or a Calypte designee, upon reasonable
         advance notice, to audit DISTRIBUTOR's premises and sales records in
         connection with this Agreement at no expense to DISTRIBUTOR. Said
         auditor shall not be permitted to record DISTRIBUTOR's customer list,
         except where customers specified by name by Calypte are the subject of
         investigation.

4.16     COMPETING PRODUCTS During the term of this Agreement, neither directly
         nor through any third party to manufacture, sell, promote, market, or
         advertise without prior written permission from Calypte, any in vitro
         diagnostic test for the detection of HIV antibodies in bodily fluids
         other than serum or plasma.

4.17     NEW PRODUCTS To accept distribution rights and obligations for new
         Products which the parties believe DISTRIBUTOR could be reasonably
         expected to sell as they may become available from time to time, and
         under such terms and conditions as the parties may negotiate in good
         faith.

ARTICLE 5   CALYPTE'S UNDERTAKINGS

Calypte agrees, during the term of this Agreement:

5.1      EXCLUSIVE DISTRIBUTOR To limit the authorized sale of the Products in
         the Territory to DISTRIBUTOR, and to take such action as may be
         necessary to ensure compliance of third parties in this regard.

5.2      FILLING ORDERS To use its best efforts to fill all orders of
         DISTRIBUTOR for delivery of the Products hereunder within forty-five
         (45) days of acceptance of DISTRIBUTOR'S order. Orders shall be placed
         in writing and mailed or transmitted by facsimile in accordance with
         the Rolling Demand Forecasting system described in Section 4.4.1
         hereof. No order from DISTRIBUTOR shall be

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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         binding upon Calypte until such order is accepted by Calypte in
         writing by mail or facsimile, such acceptance not to be unreasonably
         withheld. Calypte shall make commercially reasonable efforts to fill
         orders which are placed in addition to orders placed through the
         Rolling Demand Forecasting system. Calypte also agrees to consider on
         an individual basis, DISTRIBUTOR's proposals for Calypte to sell
         Product directly to an end-user within the Territory.

5.3      TRADEMARKS To use its best efforts to maintain the Trademarks in good
         legal standing in the Territory.

5.4      SALES MATERIAL To furnish to DISTRIBUTOR, at Calypte's expense, a
         reasonable supply of sales literature and promotional materials. The
         promotional materials may be furnished in the English language.
         DISTRIBUTOR may translate the materials at its own expense, and with
         prior approval from Calypte, such approval not to be unreasonably
         withheld. Calypte may make reasonable charges if more than a nominal
         quantity of promotional materials is supplied to DISTRIBUTOR, which
         will be agreed upon between Calypte and DISTRIBUTOR in advance.

5.5      WARRANTY To warrant the Products as set out in Article 8 below.

5.6      SALES LEADS To forward to DISTRIBUTOR sales leads and inquiries from
         customers located within the Territory.

5.7      TRAINING To provide to DISTRIBUTOR such sales, marketing, and
         technical training as may be reasonably required, at Calypte's
         facility, but not to exceed one week during each year of this
         Agreement. Costs incurred in such training excluding travel and
         accommodation, but including training materials, trainer time, and a
         reasonable amount of Product shall be borne by Calypte.

5.8      To provide telephone technical support to DISTRIBUTOR during Calypte's
         normal business hours, and to communicate to DISTRIBUTOR the status of
         any technical investigation it undertakes on behalf of DISTRIBUTOR or
         DISTRIBUTOR's customers no more than two working days after
         notification of a technical problem.

5.9      NEW PRODUCTS To offer to DISTRIBUTOR the right of first refusal on new
         Products which Calypte may develop from time to time, and which the
         parties believe DISTRIBUTOR may be reasonably expected to sell.

5.10     NO-CHARGE EVALUATION MATERIALS [*]

5.11     PACKAGING AND LANGUAGE To discuss in good faith the needs of the
         DISTRIBUTOR, as may be specified by local laws, regarding package
         inserts in the local language, as well as packaging options such as
         bulk or smaller kits sizes.

5.12     CERTIFICATE OF ANALYSIS To provide to DISTRIBUTOR with each shipment,
         Calypte's standard report of final QC testing for each lot of each
         Product shipped.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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ARTICLE 6   PRICE AND PAYMENT

6.1      [*]

6.2      [*]

6.3      CURRENCY Payment shall be made in U.S. dollars.

ARTICLE 7   SHIPPING-TITLE AND RISK-CANCELLATION

7.1      [*]

7.2      [*]

ARTICLE 8   WARRANTY - NO CONSEQUENTIAL DAMAGES - INDEMNITY

8.1      WARRANTY Calypte warrants the Products to be of sufficient quality of
         materials and manufacture as to meet the claims and specifications set
         forth in the Product's packaging and labeling when used according to
         the directions provided therein.

         EXCEPT AS OTHERWISE EXPRESSLY PROVIDED HEREIN, CALYPTE MAKES NO
         REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
         FITNESS FOR A PARTICULAR

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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         PURPOSE, OR ANY OTHER MATTER, WITH RESPECT TO THE PRODUCTS.
         DISTRIBUTOR's exclusive remedy will be for direct damages, and
         Calypte's total liability for any and all losses and damages arising
         out of any cause whatsoever ( whether such cause be based in
         contract, warranty, negligence, strict liability, other tort or
         otherwise) will in no event exceed DISTRIBUTOR's landed cost of the
         Products in respect to which such cause arises or, at Calypte's
         option, the replacement of such Products. In no event will Calypte be
         liable for incidental, consequential or punitive damages resulting
         from any cause whatsoever. Calypte warrants that at the time that the
         Products left Calypte's possession, they were deemed to be of good
         quality. In the event that a defect is identified and agreed upon by
         both parties, the invoice for the defective Product shall be rendered
         void, and a new invoice generated upon delivery of replacement
         Product. In the event that Calypte advises DISTRIBUTOR to destroy
         Product, DISTRIBUTOR shall furnish the invoice for doing so. Said
         invoice shall confirm Product destruction, and DISTRIBUTOR shall be
         reimbursed by Calypte in US dollars at the then-current exchange
         rate, or provided credit in equal amount.

8.2      DEFECTS Without limiting the generality of the foregoing, CALYPTE
         SHALL NOT BE BOUND TO MAKE GOOD ANY DEFECT IN THE PRODUCTS WHERE THE
         PRODUCTS HAVE BEEN SUBJECTED TO MISUSE, NEGLECT, OR ACCIDENTAL DAMAGE.

8.3      TRADEMARKS Calypte is the record owner of registrations for its
         trademarks in the Territory and believes it has the right to use these
         trademarks throughout the Territory. Notwithstanding, CALYPTE MAKES NO
         EXPRESS OR IMPLIED REPRESENTATION OR WARRANTY THAT THE PRODUCTS WILL
         NOT INFRINGE THE LEGITIMATE AND VALID TRADEMARKS, TRADE NAMES, OR
         OTHER INDUSTRIAL PROPERTY RIGHTS OF THIRD PARTIES IN THE TERRITORY.
         DISTRIBUTOR shall immediately notify Calypte of any such claims of
         others, and Calypte shall, at its sole option, have the right to
         assume the defense of any such claim.

8.4      INSPECTION It shall be the responsibility of DISTRIBUTOR to inspect
         the Products after taking title to same. Notwithstanding Article 8.1
         above, Calypte shall not be liable for any shortage, breakage, or
         damage to the Products or for any breach of warranty, implied or
         otherwise, unless it receives written notice of any defect or
         shortcoming within ten (10) days after the date on which DISTRIBUTOR
         takes title to the Products, and the defect or shortcoming results
         from the fault or negligence of Calypte.

8.5      INDEMNIFICATION Calypte shall indemnify and hold DISTRIBUTOR harmless
         from any claims, demands, liabilities, suits or expenses of any kind
         arising out of any misrepresentations which Calypte makes concerning
         the Product supplied by Calypte.

         Calypte shall indemnify DISTRIBUTOR for any damages or loss actually
         paid by DISTRIBUTOR resulting from a legal decision on a claim by
         third parties made against DISTRIBUTOR and which is caused by Calypte
         with respect to products made or supplied by Calypte.

         DISTRIBUTOR is responsible for, and shall hold Calypte harmless from
         any loss, claim, damage, illness or injury to persons or property
         which arises out of or pertains to the sale, use, packaging,
         advertising, or promotion of the Product, and which is caused by
         DISTRIBUTOR or DISTRIBUTOR's subdistributors, agents

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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         or employees. This provision shall survive the expiration or
         termination of this Agreement for any reason and shall be liberally
         construed in favor of Calypte.

ARTICLE 9   TERM AND TERMINATION

9.1.1    TERMINATION FOR CAUSE Calypte, at its sole option, may immediately
         terminate this Agreement with respect to the Territory, upon giving
         notice to this effect, whenever any of the following events occurs:

         (i) if any governmental unit within the Territory threatens (in the
         sole judgement of Calypte) to enact or enacts any law, decree or
         regulation which would restrict the right of Calypte to terminate or
         elect not to renew this Agreement as herein provided, or would make
         Calypte liable to DISTRIBUTOR for compensation or damages upon
         termination or failure to renew this Agreement;

         (ii) if DISTRIBUTOR at any time discontinues or abolishes its
         business, files a petition of bankruptcy or insolvency or admits in
         writing its inability to pay its debts as they become due and
         payable, or if DISTRIBUTOR is adjudicated bankrupt or insolvent, or
         if there is filed any petition seeking reorganization of DISTRIBUTOR,
         or if a receiver is appointed for all or substantially all of
         DISTRIBUTOR's property, or if DISTRIBUTOR makes an assignment for the
         benefit of creditors or if any proceedings are instituted for the
         liquidation or winding up of DISTRIBUTOR;

         (iii) if DISTRIBUTOR uses Calypte's trademarks or trade names or
         styles in any way which might deceive or mislead the consumer or
         which might in any way damage or impair the reputation or value of
         such trademarks, trade names, or styles;

         (iv) if DISTRIBUTOR fails to comply with any of the terms or
         conditions herein contained and, after notice by Calypte requiring
         DISTRIBUTOR to make good such default, DISTRIBUTOR fails to cure such
         default within sixty (60) days after receipt of such notice;

         (v) if DISTRIBUTOR is at any time nationalized or falls under the
         control of any governmental unit within the Territory;

         (vi) if DISTRIBUTOR's authority to carry on business is cancelled by
         competent authorities;

         (vii) if control of DISTRIBUTOR should be transferred to another
         party, whether such party is a competitor of Calypte or otherwise; or

         (viii) all Products are deleted from Schedule 1.

9.1.2    DISTRIBUTOR, at its sole option, may immediately terminate this
         Agreement with respect to the Territory, upon giving notice to this
         effect, whenever any of the following events occurs:

         (i) if Calypte at any time discontinues or abolishes its business,
         files a petition of bankruptcy or insolvency or admits in writing its
         inability to pay its debts as they become due and payable, or if
         Calypte is adjudicated bankrupt or insolvent, or if there is filed any
         petition seeking reorganization of Calypte, or if a receiver is
         appointed for all or substantially all of Calypte's property, or if
         Calypte makes

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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         an assignment for the benefit of creditors or if any proceedings are
         instituted for the liquidation or winding up of Calypte; or

         (ii) if Calypte fails to comply with any of the terms or conditions
         herein contained and, after notice by DISTRIBUTOR requiring Calypte to
         make good such default, Calypte fails to cure such default within
         sixty (60) days after receipt of such notice.

9.1.3    Upon termination or expiration of this Agreement for any reason with
         respect to the Territory:

         i) at Calypte's option, DISTRIBUTOR may sell its remaining inventory
         of Product within the Territory, or shall make available to Calypte or
         Calypte's designee, all current stocks of Product held by DISTRIBUTOR
         with a minimum of four (4) months' expiration remaining, at
         DISTRIBUTOR's landed cost, EXW DISTRIBUTOR's warehouse, which shall
         include any duty, freight, insurance documentation and inland freight
         to warehouse distribution. In the event that DISTRIBUTOR has firm
         supply obligations with customers that extend beyond the termination
         date, and DISTRIBUTOR advises Calypte of these with full details,
         Calypte agrees to continue to supply DISTRIBUTOR with Product for
         these customers only, and only for the duration of said obligation or
         for a maximum of twelve (12) months beyond the date of termination,
         whichever comes first.

         ii) DISTRIBUTOR shall at its own expense return to Calypte or its
         designee all Confidential Information furnished by Calypte in
         accordance with Article 5.2 hereof, as well as all sales literature,
         catalogues, samples, and other promotional materials supplied by
         Calypte;

         iii) Calypte will not be liable to pay to DISTRIBUTOR any termination
         compensation, benefits or damages of any kind whatsoever, whether for
         DISTRIBUTOR's loss of present or prospective profits, anticipated
         sales, expenditures, investments or commitments made in connection
         with this Agreement, or due to the termination of any of
         DISTRIBUTOR's employees, agents, or subdistributors, or due to any
         other matter or cause whatsoever, and whether provided by any current
         or future law, regulation or interpretation thereof by any authority
         exercising jurisdiction over this Agreement, and;

         iv) all obligations of Calypte shall be canceled, but such expiration
         or termination will not affect any of Calypte's rights hereunder, and
         Calypte will further have the right, immediately upon such expiration
         or termination, to appoint a new distributor or sales representative.
         Such expiration or termination will not affect DISTRIBUTOR's
         obligation to make payment for any orders of the Products which
         remain unpaid at such time.

ARTICLE 10  ASSIGNMENT

         DISTRIBUTOR shall not be entitled to assign its rights and obligations
         under this Agreement without the prior written consent of Calypte. In
         the context of this Agreement, a change in control or ownership of the
         DISTRIBUTOR, whether involving a competitor of Calypte or otherwise,
         shall constitute assignment, and in accordance with 9.1.1(vii) Calypte
         may, at its discretion, terminate this Agreement.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

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ARTICLE  11 WAIVER The failure of either party to assert a right under, or to
         enforce at any time or for any period of time, the provisions hereof
         or the failure of either party to exercise an option herein shall not
         be construed as a waiver of such provision or option and shall in no
         way affect that party's right to enforce such provisions or exercise
         such options. A waiver of any breach of any provision of this
         agreement shall not be construed as a continuing waiver of other
         breaches of the same or other provisions of this agreement.

ARTICLE 12  ENTIRE AGREEMENT

         With the exception of previously signed Confidentiality Agreements,
         this Agreement cancels and supersedes any previous understandings or
         agreements, oral or written, between the parties relating to the
         subject matter hereof, including any previously existing
         distributorship arrangement. This Agreement expresses the complete
         and final understanding of the parties with respect to the subject
         matter hereof, and may not be changed in any way except upon the
         explicit intention of both parties expressed by a signed written
         agreement. Any terms or conditions stated in DISTRIBUTOR's purchase
         orders inconsistent with this Agreement shall be null and void.

ARTICLE 13  SEVERABILITY

         If any provision of this Agreement shall be found by a court of
         competent jurisdiction to be invalid or unenforceable, the invalidity
         or unenforceability of such provision shall not affect the other
         provisions of this Agreement and all provisions not affected by such
         invalidity shall remain in full force and effect but that in any
         event, the provisions concerning payment for the Product shall be
         binding upon the parties.

ARTICLE 14  NOTICES

14.1     NOTICE Any notice required or permitted by this Agreement shall be in
         writing and in the English language, and shall be delivered personally
         or by registered air mail, postage prepaid, or by facsimile, addressed
         to the parties as follows:

If to Calypte:                      Calypte Biomedical Corporation
                                    1265 Harbor Bay Parkway
                                    Alameda, California  94502
                                    United States of America

                                    Telephone: 510-749-5100
                                    Facsimile: 510-814-8408
                                    Attention: President

If to DISTRIBUTOR:                  Biobras S.A.
                                    Praca Carlos Chagas 49, 4(DEG.) Andar
                                    Belo Horizonte, MG CEP 30170-020

                                    Telephone: 011-55-31-291-9877
                                    Facsimile:  011-55-31-291-5369
                                    Attention: Diagnostics Division Director

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

11

<PAGE>

14.2     RECEIPT Any notice sent by registered prepaid air mail properly
         addressed and posted shall be deemed to have been received ten (10)
         days after it is delivered to the postal authorities in the country of
         the party by whom it is sent. If sent by facsimile, a copy of the
         facsimile shall be sent promptly by registered prepaid air mail to the
         addressee.

14.3     VERBAL NOTICE Nothing contained herein shall justify or excuse
         failure to give verbal notice for the purpose of informing the other
         party thereof when prompt notification is appropriate, but such verbal
         notice shall not satisfy the requirement of written notice.

ARTICLE 15  APPLICABLE LAWS

15.1     EXPORT LAWS Calypte is subject to U.S. laws and regulations governing
         the export of U.S. products. DISTRIBUTOR agrees that it will not
         directly or indirectly engage in any acts which would cause Calypte to
         be found in violation of such laws or regulations.

15.2     PAYMENTS DISTRIBUTOR acknowledges that certain laws of the United
         States may result in the imposition of sanctions on Calypte and its
         employees in the event that offers, promises, or payments are
         directly or indirectly made to government officials or others for the
         purpose of influencing decisions favorable to Calypte, and, therefore
         DISTRIBUTOR agrees that neither it nor its employees will commit such
         acts or engage in such activities and that DISTRIBUTOR shall defend,
         indemnify, and hold Calypte harmless for any damages, claims,
         liabilities and expenses which arise or allegedly arise from
         DISTRIBUTOR's violation of the obligations of articles 15.1 or 15.2.

15.3     ASSURANCES DISTRIBUTOR agrees to furnish to Calypte , by affidavit or
         other reasonable means from time to time at Calypte's request, and to
         the reasonable satisfaction of Calypte, assurances that the
         appointment of DISTRIBUTOR hereunder, its activities under this
         Agreement, and the payment to DISTRIBUTOR of any monies or
         consideration contemplated hereunder are proper and lawful under the
         laws in force in the Territory. DISTRIBUTOR further represents that
         no person employed by it is an official of any government agency or a
         corporation owned by a government unit within the Territory and that
         no part of any monies or consideration paid hereunder shall accrue
         for the benefit of any such official.

15.4     TERRITORY LAWS If Calypte determines that the appointment or use of
         DISTRIBUTOR is not permitted under the laws and regulations in force
         in the Territory, Calypte has the right, at its sole discretion and
         upon notice to DISTRIBUTOR, to terminate this Agreement as Calypte
         sees fit. Upon notice of this decision, DISTRIBUTOR will cease its
         activities under this Agreement and shall not seek damages or
         compensation in any form, according to Article 9 of this Agreement.

ARTICLE 16  GOVERNING LAW
         This Agreement and the obligations of the parties hereunder shall be
         governed and construed in accordance with the laws of the State of
         California, U.S.A.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

12

<PAGE>

ARTICLE 17  FORCE MAJEURE
         Calypte and DISTRIBUTOR will be excused from failure to perform under
         this Agreement and will not be liable in any way for any loss if such
         failure is due to causes beyond the reasonable control of either
         party, including but not limited to, natural disasters such as
         earthquakes or floods, fires, riots, strikes and other labor
         disputes, war conditions, shortage of raw materials or government
         action for the period any such conditions exist.

ARTICLE 18  HEADINGS
         The headings used herein are for convenience only and in no way affect
         the liabilities, obligations, or responsibilities of the parties
         hereto.

IN WITNESS WHEREOF, the parties hereto have executed this Agreement.

CALYPTE BIOMEDICAL CORPORATION

By: /s/ Nancy E. Katz
   ----------------------------

Title: President
      -------------------------

Date: 5/19/00
     --------------------------

BIOBRAS S.A.

By: /s/ Humberto de cerega Mendez
   ------------------------------

Title: Director
      -------------------------

Date: 5/11/00
     --------------------------

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

13

<PAGE>

                              SCHEDULE 1 - PRODUCTS

Calypte HIV-1 Urine EIA Test Kit  An enzyme immunoassay in microwell format
for the detection of antibodies to HIV-1 in urine.

                        Cat. No. 700000          480 tests
                        Cat. No. 700001          192 tests

Cambridge Biotech HIV-1 Serum Western Blot Test Kit.  A Western Blot
supplemental immunoassay for the analysis of serum or plasma samples that are
repeatedly reactive on a serum or plasma HIV-1 EIA. Cat. No. 98002    27 tests

Cambridge Biotech HIV-1 Urine Western Blot Test Kit.  A Western Blot
supplemental immunoassay for the analysis of urine samples that are
repeatedly reactive on the Calypte HIV-1 Urine EIA. Cat. No. 98076    27 tests

Cambridge Biotech HTLV I/II Serum Western Blot Test Kit.  A Western Blot
supplemental immunoassay for the analysis of serum or plasma samples that are
repeatedly reactive on a serum or plasma HTLV EIA.  Cat. No. 98051    27 tests

                               SCHEDULE 2 - PRICE

[*]
                               SCHEDULE 3 - MINIMA

[*]
                             SCHEDULE 4 - TRADEMARKS

Calypte name and corporate logo
Calypte hummingbird logo
Sentinel tradename
Cambridge Biotech name and corporate logo

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

14<PAGE>
                                                                  Exhibit 10.71

                         CALYPTE BIOMEDICAL CORPORATION

                             1265 HARBOR BAY PARKWAY
                                ALAMEDA, CA 94502

May 16, 2000

Beijing Hua Ai Science and Technology
 Development Co. Ltd.
National Center For AIDS Prevention and Control
27 NanWei Road
Beijing, People's Republic of China
100050

Re:   AUTHORIZED INTERNATIONAL EXCLUSIVE DISTRIBUTOR AGREEMENT FOR PEOPLE'S
      REPUBLIC OF CHINA

Gentlemen:

         This letter sets forth our Agreement with Beijing Hua Ai Science and
Technology Development Co. Ltd. (the "Distributor"), under The National
Center For AIDS Prevention And Control ("NCAIDS, CHINA") and the Chinese
Academy of Preventive Medicine, with respect to the distribution by the
Distributor, in the People's Republic of China, Hong Kong and Macau (the
"Territory"), of Calypte's Human Immunodeficiency Virus ("HIV") diagnostic
products (the "Products"). Subject to Section 21(g), this Agreement will
become effective as of the date hereof (the "Effective Date").

         1.       APPOINTMENT AS CALYPTE'S EXCLUSIVE DISTRIBUTOR IN THE
TERRITORY. [*]

         2.       DISTRIBUTOR GENERAL OBLIGATIONS. In addition to other
Distributor obligations specifically described in other parts of this
Agreement, Distributor will have the following obligations:

                  (a) DISTRIBUTE CALYPTE PRODUCTS. Distributor will use its best
efforts, with our cooperation, to promote the distribution and sale of Calypte
Products within the Territory in accordance with this Agreement and with all
applicable laws. Distributor also agrees not to distribute any assay for the
detection of HIV or antibodies to HIV based on non-blood methods other than
those manufactured by the Company.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       1
<PAGE>

                  (b) DISTRIBUTOR PERSONNEL. Distributor will train and maintain
a sufficient number of capable technical and sales personnel to have the
knowledge and training necessary to inform Distributor customers as to the
features and capabilities of Calypte Products and, if necessary, competitive
products, and to support Calypte Products in accordance with Distributor
obligations under this Agreement. Distributor and Calypte will cooperate with
respect to training of Distributor's technical and sales personnel concerning
Calypte Products, including subsequent agreement by us in writing, as an
amendment to this Agreement, as necessary, as to the nature of training, the
amount of training time, and which of us will pay for travel and living expenses
for training Distributor personnel.

                  (c) CUSTOMER SUPPORT. Distributor will provide pre-sales and
post-sales service and support for all Calypte Products located in the
Territory. Distributor will timely respond to Distributor customers' general
questions concerning use of Calypte Products. Distributor also will assist
customers in the diagnosis and correction of problems encountered in using
Calypte Products, and will keep Calypte apprised of the general nature of such
questions and of such problems.

                  (d) CERTAIN GOVERNMENTAL MATTERS. Distributor agrees it
will use its best efforts to obtain as soon as possible all necessary
governmental approvals needed to distribute the Product. [*] Distributor will
cause the registration rights to be under the name of Calypte. Calypte will
be under no obligation to ship Calypte Products to Distributor until
Distributor have provided us with satisfactory evidence that the approvals,
notifications or registrations referred to in this paragraph either are not
required or that they have been timely and properly obtained.

                  (e) RECORDS. During the term of this Agreement and for at
least twelve (12) months after termination of this Agreement, Distributor will
maintain records and contracts relating to Distributor's distribution of Calypte
Products, and Distributor will permit examination of those records and contracts
by Calypte's authorized representatives at all reasonable times.

                  (f) REPORTS. Within thirty (30) days of the end of each
quarter, Distributor will provide Calypte with a written report showing: (a)
Distributor shipments of Calypte Products in the Territory by number of tests;
(b) forecasts of Distributor anticipated orders of Calypte Products; and (c)
Distributor's current inventory levels of Calypte Products.

         3.       DISTRIBUTOR MINIMUM PURCHASE REQUIREMENTS. [*]

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       2
<PAGE>

[*]
         4.       OUR MUTUAL OBLIGATIONS.

                  (a) COOPERATION TO DISCUSS MARKET CONDITIONS. Calypte and
Distributor will discuss with each other any market information that comes to
either of our attention concerning Calypte, Calypte Products, Calypte's market
position or the continued competitiveness of Calypte Products in the Territory,
and related to market conditions for HIV diagnostic products, sales forecasting
and product planning relating to Calypte Products.

                  (b) COSTS AND EXPENSES. Except as expressly provided in this
Agreement or otherwise agreed to in writing by us with Distributor, each of us
will pay our own costs and expenses that each party separately incurs in
performing our separate obligations under this Agreement.

                  (c) COMPLIANCE WITH LAWS. Each of us will comply with all
international, national, state, regional and local laws and regulations ("Laws")
that are applicable to us. In particular, (i) Calypte will comply with all Laws
applicable to our manufacture and sale to Distributor of Calypte Products,
including without limitation all applicable regulations of the U.S. Food and
Drug Administration (the "FDA), and (ii) Distributor will comply with all Laws
applicable to Distributor importation, storage, sale and support of Calypte
Products in the Territory.

         5.       OUR REPRESENTATIONS AND WARRANTIES TO DISTRIBUTOR CONCERNING
CALYPTE PRODUCTS.

                  (a) GENERAL. Calypte represents to Distributor that Calypte
possesses good and marketable title to whatever Calypte Products Calypte shall
sell to Distributor under this Agreement and that such Calypte Products: (a)
have been manufactured by Calypte in accordance with our quality control
processes and standards and with all applicable requirements of the applicable
regulatory body or agency within the Territory, (b) conform to our applicable
specifications for such Calypte Products and are free from defects in design,
materials and workmanship, (c) are of good merchantable quality and fit for
their intended purposes, and (d) will pass the testing standards required by
State Drug Administration in China ("SDA") for the importation of the Calypte
Products into China. [*]

                  (b) LIMITED WARRANTY. Our only warranty for Calypte Products
is as set out in our written warranty accompanying Calypte Products. Calypte
disclaims and excludes all other warranties for Calypte Products, including, to
the extent permitted by applicable law, all implied

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       3
<PAGE>

warranties, including but not limited to implied warranties of
merchantability, fitness for a particular purpose and noninfringement.
Calypte can change its warranty at any time, but Calypte will give
Distributor as much advance notice in writing of any such change as possible.
To the extent that any published warranty provisions of Calypte as to an
applicable Calypte Product shipped by us to Distributor under this Agreement
are different than the applicable warranty for Calypte Products made by us
under this Agreement, the provisions of our published Calypte warranty will
control.

                  (c) DISTRIBUTOR WARRANTIES. Distributor will make no warranty,
guarantee or representation, whether written or oral, to anyone else whether on
Distributor's own or on Calypte's behalf, with respect to Calypte or Calypte
Products, unless Calypte has specifically authorized Distributor to do so before
Distributor makes such warranty, guarantee or representation.

         6.       OUR PRICES TO DISTRIBUTOR; DISTRIBUTOR PAYMENT TO US.

                  [*]

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       4
<PAGE>

[*]

         7.       ORDER PROCEDURE AND SHIPMENT.

                  (a) FORECASTS. Distributor will give Calypte written
forecasts, at least three months before the expected shipment date of the order,
of Distributor's expected orders for Calypte Products.

                  (b) CALYPTE ACCEPTANCE. All orders Distributor places for
  Calypte Products will be subject to acceptance in writing by us at our
  principal place of business and will not be binding until the earlier of the
  date Calypte accepts the order or ships it, and, in the case of acceptance by
  shipment, only as to the portion of the order Calypte actually ships.
  Distributor shall have the right to reject any Calypte Products not having a
  shelf life of a minimum of nine months.

                  (c) CONTROLLING TERMS. The terms and conditions of this
Agreement and of the applicable Calypte invoice or confirmation will apply to
each order accepted or shipped by us to Distributor under this Agreement. To
prevent confusion, (i) if there is a conflict between this Agreement and our
invoice or confirmation, the terms of this Agreement will control, (ii) the
provisions of Distributor's form of purchase order or other business forms will
not apply to any order even if Calypte has otherwise acknowledged or accepted
such form.

                  (d) CALYPTE RIGHTS WITH RESPECT TO ORDERS. Calypte can cancel
any orders that Distributor have placed and which Calypte has accepted, or
Calypte can refuse or delay shipment of the order or orders, or parts of the
orders, if Distributor: (i) fails to make any payment to Calypte that
Distributor is required to make under this Agreement or under any Calypte
invoice or acceptance document; or (ii) otherwise fails to comply with what
Calypte, in good faith, believes to be the significant terms and conditions of
this Agreement. No such cancellation, refusal or delay will be a termination of
this Agreement unless Calypte specifically so states to Distributor in writing.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       5
<PAGE>

                  (e) CALYPTE RIGHT TO ALLOCATE AMONG ORDERS. If orders for
  Calypte Products exceed our available inventory, Calypte will allocate our
  available inventory among our customers, and make deliveries to Distributor
  and other customers of ours, on a basis Calypte believe to be fair, in our
  sole discretion, and without liability to Distributor because of the method of
  allocation chosen or its implementation. In any event relating to this
  paragraph, Calypte will not be liable for any damages, direct, consequential,
  special or otherwise, to Distributor or to any other person for our failure to
  deliver or for any delay of Calypte Products for any reason whatsoever.

         8.       LABELING AND OTHER MARKETING MATERIALS.

                  (a) GENERAL OBLIGATIONS. Distributor will distribute Calypte
Products with all packaging, warranties and disclaimers, labeling and other
instructions as shipped from Calypte without any change to them except as
Calypte may approve in advance of Distributor use of them. Distributor will make
no representations, warranties or guarantees to any third party with respect to
the specifications, features or capabilities of Calypte Products that are
inconsistent with the literature distributed by Calypte with respect to such
Calypte Products.

                  (b) TRANSLATIONS. If Distributor determines it is necessary or
desirable in order for Distributor to distribute Calypte Products in the
Territory, Distributor will send Calypte Chinese translation of the labels of
Calypte Products and Calypte will include such Chinese translations in the
labels on the Calypte Products. Calypte will own all rights to those translated
materials unless this Agreement is terminated because of our breach, in which
case Distributor will own all rights only to the translation which Distributor
made or had someone else make, but not to the underlying materials.

         9.       USE OF OUR TRADEMARKS, TRADE NAMES, LOGOS, DESIGNATIONS AND
COPYRIGHTS. Calypte authorizes Distributor to use Calypte's trademarks, trade
names, logos and designations that Calypte uses for Calypte Products, only
during the term of this Agreement in connection with Distributor advertisement,
promotion and distribution of Calypte Products in the Territory. Distributor
will use them, as Calypte supplies them to Distributor, in Distributor
advertising and promotional materials and on all containers and storage media
for Calypte Products, and Distributor will not attach any additional trademarks,
trade names, logos or designations to any Calypte Product, nor will Distributor
use any Calypte trademark, trade name, logo or designation in connection with
any non-Calypte Product, without our prior written approval. Distributor has
only the above described right to use our marks and Distributor has no ownership
rights to them, and cannot use them after this Agreement expires or terminates.

         10.       CHANGES BY CALYPTE TO CALYPTE PRODUCTS. Calypte can make
whatever changes to Calypte Products as Calypte think in good faith are
necessary or appropriate, but Calypte will give Distributor as much advance
written notice as Calypte can before Calypte makes any such change. Calypte
will cooperate with Distributor to obtain whatever new or changed approvals
Distributor may need from any regulatory or other agency within the Territory
to allow Distributor to distribute and sell the modified Calypte Products in
the Territory. To the extent allowed by law, Calypte will continue to make
the unmodified Calypte Products available to Distributor until Distributor
can obtain the necessary regulatory approvals for the modified Calypte
Products. Calypte will have the right to stop production of or to make
changes to any Calypte Product to the extent that Calypte believe in good
faith that Calypte must do so under applicable law.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       6
<PAGE>

         11.       HANDLING OF PROBLEMS WITH CALYPTE PRODUCTS.

                  (a) COMPLAINTS AND REJECTIONS. Distributor will promptly
notify Calypte if any Calypte Product is found, upon incoming inspection by
Distributor, to be defective or to fail to meet Calypte's applicable written
specifications or otherwise to be defective. Distributor and Calypte will
discuss in good faith the resolution of any such problem, provided, however,
that final resolution of any such problem will be at Calypte's sole discretion.
If either of us receives any complaint regarding any Calypte Product from a
third party, including without limitation a rejection by any of Distributor's
customers of any Calypte Product or return by any customer of any Calypte
Product to Distributor as a result of an alleged failure of such Calypte
Product's performance, whichever of us receives the complaint will notify the
other in writing as to such event within twenty-four (24) hours after receipt of
such complaint, and will provide all information necessary to enable the other
to comply with applicable regulatory requirements in a timely fashion.
Distributor will be responsible for evaluating in detail all complaints from
Distributor customers as to Calypte Products and will advise Calypte in writing
of Distributor's findings. Calypte will attempt to assist Distributor in
addressing any issues or alleged problems in Product performance which
Distributor cannot remedy through Distributor's own technical support.
Distributor also agrees to provide Calypte on a monthly basis a summary of all
complaints that Distributor has received and if and how they were resolved.
Calypte will provide to Distributor a form for this purpose, the design of which
has been registered with the U.S. FDA. Product is not to be returned to Calypte
unless or until Calypte provides to Distributor a Returned Goods Authorization
number. If any Calypte Products are rejected because of quality problems
associated with production, Calypte shall reimburse Distributor for all direct
costs and expenses incurred by Distributor for such rejected products such as
shipping expenses, product costs, handling, notification, testing or costs of
destruction.

                  (b) PRODUCT RECALL. If either of us, or any applicable
regulatory body or agency, recalls any Calypte Product, on the basis that those
Calypte Products are believed or alleged to violate any provision of applicable
law, then unless Distributor and Calypte agree otherwise in writing, whichever
of us initiates the recall will bear all costs and expenses of the recall,
including, without limitation, expenses or obligations to third parties, the
cost of notifying customers and costs associated with the shipment from
Distributor customers to Distributor or to Calypte of recalled Calypte Products
sold by Distributor pursuant to Distributor rights under this Agreement. Calypte
and Distributor will cooperate fully with each other in effecting any recall of
the Calypte Products, including communications with customers and other
purchasers or users.

                  (c) OTHER NOTIFICATION. Distributor will notify us in writing
of any claim or proceeding involving Calypte Products, other than claims
procedures for claims against each other, within ten (10) days after Distributor
learn of the claim or proceeding. Distributor also will notify us in writing not
more than thirty (30) days after any change in Distributor's executive
management or any transfer of all or substantially all of Distributor's assets.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       7
<PAGE>

         12.      TERM AND TERMINATION OF THIS AGREEMENT.

                  (a) TERM. This Agreement is for an initial term commencing as
of the Effective Date of this Agreement and will expire automatically on the
date two years and six months after the date of registration of the Calypte
Products (the "Initial Term") unless Distributor renews the Agreement as
discussed below. If Distributor has purchased and paid for all of the Required
Minimum Purchases through the Initial Term as set forth on Exhibit B to this
Agreement, then Distributor may, by giving us written notice at least 180 days
before the last date of the Initial Term, extend the term of this Agreement for
an additional three years (the "Renewal Term").

                  (b) TERMINATION. This Agreement may be terminated prior to the
expiration of the Initial Term or of the Renewal Term as follows:

                                    (i)     TERMINATION FOR FAILURE TO OBTAIN
GOVERNMENT APPROVAL. This Agreement may be terminated by Calypte if the Product
has not been approved for commercial sale in the Territory by the relevant
governmental authorities prior to December 31, 2000.

                                    (ii)    TERMINATION FOR FAILURE TO FULFILL
OBLIGATIONS. This Agreement may be terminated by either party if the other fails
to perform one or more of its obligations under this Agreement, and that failure
is not cured within the time period set out in written notice from the
non-failing party, which time period will be at least thirty (30) days for
anything except failure to make payment, and at least ten (10) days for failure
to make payment.

                                    (iii)   VOLUNTARY TERMINATION.  Either of us
also may terminate this Agreement at will, at any time during the term of this
Agreement, with or without cause, by written notice given to the other not less
than six (6) months prior to the effective date of such termination.

                                    (iv)    CALYPTE SEPARATE RIGHTS TO
TERMINATE. Calypte may also terminate this Agreement immediately by written
notice to Distributor if Distributor is merged, consolidated, sells all or
substantially all of its assets, or if there is, in our good faith view, any
substantial change in management or control of Distributor, or if any bill or
regulation is introduced into or passed by the legislature or other governing
body of the Territory that would grant Distributor compensation, outside of this
Agreement, upon any termination or expiration of this Agreement. Calypte also
may terminate this Agreement immediately by written notice to Distributor if
Calypte become legally unable to sell Calypte Products to Distributor because of
some other party's claim that Calypte Products infringe that party's proprietary
rights, and if Calypte cannot then obtain from that third party a right for
Distributor to continue to purchase and sell Calypte Products within the
Territory.

                                    (v)     AUTOMATIC TERMINATION.  This
Agreement will terminate automatically if a receiver is appointed for either of
us or for our respective property, or if either of us makes an assignment for
the benefit of our respective creditors, or if any proceedings are

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       8
<PAGE>

commenced by, for or against either of us under any bankruptcy, insolvency or
debtor's relief law, or if either of us is liquidated or dissolved.

                  (e) [SIC] ORDERS AFTER TERMINATION NOTICE. Regardless of
which of us terminates this Agreement, Calypte can reject all or part of any
orders received from Distributor after the notice of termination is sent but
prior to the effective date of termination, if availability of Calypte
Products is insufficient at that time, in our good faith view, to meet the
needs of Calypte and our other customers fully.

                  (f) [SIC] EFFECT OF TERMINATION OR EXPIRATION. [*]

                           (iii)    For a period of twelve (12) months after the
date of termination or expiration, Distributor will make available to Calypte
for inspection and copying all portions of Distributor records that pertain to
Distributor performance of Distributor obligations and representations under
this Agreement.

                           (iv)     Distributor will stop using any Calypte
trademark, trade name, logo or designation.

                  (g) [SIC] NO DAMAGES FOR TERMINATION OR EXPIRATION. Neither
of us will be liable to the other for damages of any kind, including
incidental or consequential damages, nor for any reimbursement or damages for
the loss of goodwill, prospective profits or anticipated income, or on
account of any expenditures, investments, leases or commitments made by
either of us, arising from or connected with the termination or expiration of
this Agreement in accordance with its terms. Distributor and Calypte waive
any right either of us may have to receive any compensation or reparations on
termination or expiration of this Agreement under the law of the Territory or
otherwise, other than as expressly provided in this Agreement, and agree that
Distributor has no expectation and has received no assurances that any
investment by Distributor in the promotion of Calypte Products will be
recovered or recouped or that Distributor will obtain any anticipated amount
of profits by virtue of this Agreement. Distributor also agrees that

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       9
<PAGE>

Distributor will not have or acquire by virtue of this Agreement or otherwise
any vested, proprietary or other right in the promotion of Calypte Products
or in "goodwill" created by its efforts under this agreement. Distributor
understands that Calypte would not have entered into this Agreement but for
the limitations of liability as set forth herein.

                  (h) [SIC] SURVIVAL. Calypte's rights and Distributor's
obligations to pay Calypte all amounts due under this Agreement, as well as
Paragraphs 2(c) and (e), 8b, 9, 11, 12 (e) and (f), and 13-20 of this
Agreement will survive any termination or expiration of this Agreement.

         13.      INDEMNIFICATION.

                  (a) CALYPTE'S INDEMNIFICATION OF DISTRIBUTOR. Calypte will, at
its expense, defend Distributor against and, subject to the limitations in this
Agreement, pay all costs and damages made in settlement or awarded against
Distributor, resulting from any claim based on an allegation that a Calypte
Product as supplied by us to Distributor under this Agreement infringes a U.S.
patent or copyright of anyone else. Distributor will cooperate with Calypte in
our defense of any such claim, and Calypte will have sole authority to settle
the claim. Calypte will not be liable to Distributor for any claim arising from
or based upon the combination, operation or use of any Calypte Product with
product not supplied by Calypte, or arising from any alteration or modification
by Distributor or Distributor's customers of Calypte Products. The obligations
set out in this Paragraph 13(a) are our only obligations to Distributor with
respect to any claim by a third party that Calypte Products infringe any other
party's proprietary rights.

                  (b) DISTRIBUTOR INDEMNIFICATION OF CALYPTE. Distributor will
indemnify Calypte (including paying all reasonable attorneys' fees and costs of
litigation) against and hold Calypte harmless from, any claims by any other
party resulting from Distributor acts, omissions or misrepresentations.

         14.      LIMITATIONS OF LIABILITY. Neither of us will be liable to
the other or to the other's vendors or customers for any lost profits or for
any direct, indirect, incidental, consequential, punitive or other special
damages suffered by either of us, or by such other parties, arising out of or
related to this Agreement or to Calypte Products, for any legal or equitable
action, under whatever theory, even if either or both of us have been advised
of the possibility of such damages.

         15.      CONFIDENTIALITY. Each party will keep as confidential all
information which each party receives from the other and which is marked as
confidential by the sender of the information. Neither of us will use the
other's confidential information except in performance of this Agreement and
each party will disclose such information to third parties except to the extent
required by law, and then will let the other party know immediately in writing
if such required disclosure is to be made. Neither of us will have any
obligation under this Paragraph 15 with respect to any information of the other
that the other has disclosed to anyone else without this obligation of
confidentiality, or which otherwise is known to the public not due to a breach
by one of us of our obligations under this Paragraph 15.

         16.      RESOLVING DISAGREEMENTS.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       10
<PAGE>

                  (a) GENERAL. Distributor and Calypte, and the other parties to
this Agreement, will seek to resolve any disagreement Calypte may have under
this Agreement by cordial discussion of our senior managers and executives. If,
within thirty (30) days after one of us has given written notice to the other of
a disagreement, and the parties cannot resolve the matter on their own as
discussed in this Paragraph 16(a), then either of us, by written notice to the
other, can refer the matter to arbitration, which will be binding and which will
be conducted as next described.

                  (b) BINDING ARBITRATION. All disputes or disagreements
between us arising out this Agreement, or in respect of any defined legal
relationship associated with this Agreement, which have not been resolved by
our mutual discussion as provided above, will, upon the written demand by
either of us mentioned above, be referred to and finally resolved by
arbitration in Beijing under the rules of a bona fide international
commercial arbitration organization (such as the International Chamber of
Commerce and the Foreign Economic and Trade Arbitration Commission of China
Council for the Promotion of International Trade in Beijing) which is
mutually acceptable to both parties. The arbitration will be conducted in the
English language. Relevant documents in other languages will be translated
into English if the arbitrators so direct. A written transcript in English of
the hearing will be made and furnished to the parties. The applicable
substantive law will be the law of the State of California, U.S.A., excluding
the Convention on Contracts for the International Sale of Goods and excluding
that body of law known as conflict of laws unless the arbitrators decide that
the applicable law should be the laws of China with respect to events
occurring in China, in which case the laws of China shall apply. The
arbitrators will decide in accordance with the terms of this Agreement and
will take into account any appropriate international trade usages applicable
to the transaction. The arbitrators will state the reasons upon which the
award is based.

                  (c) ENFORCEMENT OF ARBITRATION AWARD. The award of the
arbitrators will be final and binding upon both of us, and either of us can
enter judgment upon the award in any court with jurisdiction. Either of us can
make an application to any such court for judicial acceptance of the award and
for an order of enforcement. Each of us consents to the enforcement of any
judgment rendered in the United States or China in any enforcement action. Any
defenses either of us might raise concerning the validity and enforceability of
the arbitration judgment will be deemed waived unless first raised in a court
of competent jurisdiction in the United States.

         17.      OUR RELATIONSHIP. Distributor's relationship with Calypte
during the term of this Agreement will be that of an independent contractor.
Neither party will have any power, right or authority to bind the other, or
to assume or create any obligation or responsibility, express or implied, on
behalf of the other or in the other's name, except as is specifically set out
in this Agreement.

         18.      ASSIGNMENT. Neither party can assign this Agreement unless the
other approves in writing before the assignment, except that Calypte can assign
this Agreement to any party which purchases all or substantially all of
Calypte's assets, or to the surviving entity in any merger or reorganization in
which Calypte is not the surviving entity. The provisions of this Agreement

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       11
<PAGE>

will be binding upon and inure to the benefit of the parties, our respective
successors and permitted assigns.

         19.      GUARANTEE BY NCAIDS, CHINA OF DISTRIBUTOR PERFORMANCE OF
DISTRIBUTOR OBLIGATIONS. NCAIDS, CHINA hereby unconditionally and irrevocably
guarantees in full the performance of all of Distributor's obligations under
this Agreement, and such guarantee as to amounts Distributor may owe Calypte is
a guarantee of payment and not just of collection.

         20.      JOINT VENTURE. Calypte and Distributor hereby agree to
explore the possibility of establishing a joint venture to manufacture the
Calypte Product in China. The specifics of capitalization, location,
ownership, and registration will be determined in good faith negotiations
between the two parties.

         21.      GENERAL PROVISIONS.

                  (a) NOTICES. All notices and demands under this Agreement will
be in writing and will be delivered by personal delivery, including
internationally recognized courier service, or by facsimile, at the address of
the receiving party set out below our signatures, as either of us may change our
address by notice to the other in accordance with this Paragraph 21. Deliveries
by personal delivery will be deemed made when delivered, and deliveries by
facsimile will be deemed made upon confirmed facsimile transmission.

                  (b) CONTROLLING LAW; SEVERABILITY. This Agreement will be
governed by and construed in accordance with the laws of the State of
California, excluding the Convention on Contracts for the International Sale
of Goods and excluding that body of law known as conflict of laws unless the
arbitrators appointed pursuant to Section 16(b) decide that the laws of China
shall apply with respect to events occurring in China, in which case the laws
of China shall apply.

                  (c) SEVERABILITY. If any of the provision of this Agreement is
held by a court or other tribunal of competent jurisdiction to be unenforceable,
such provision will be enforced to the maximum extent permissible and the
remaining portions of this Agreement will remain in full force and effect.

                  (d) FORCE MAJEURE. Neither of us will be responsible for any
failure to perform due to unforeseen circumstances or to causes beyond
Distributor or our reasonable control, including but not limited to acts of God,
war, riot, embargoes, acts of civil or military authorities, fire, floods,
accidents, strikes, failure to obtain export licenses or shortages of
transportation, facilities, fuel, energy, labor or materials. If there is such a
delay, whichever of us is so delayed may defer the date of performance of the
relevant obligations under this Agreement for a period equal to the time of such
delay.

                  (e) ENTIRE AGREEMENT. This Agreement is our complete agreement
with respect to the specific matters set out in this Agreement, and supersedes
in their entirety any and all written or oral agreements previously existing
between any of us with respect to such specific matters. Any changes to this
Agreement must be in writing and signed by at least Calypte and Distributor.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       12
<PAGE>

                  (f) CHOICE OF LANGUAGE. The original of this Agreement has
been written in English and Chinese, and the English-language and the
Chinese-language versions of this Agreement will have equal force in
interpreting this Agreement.

                  (g) AUTHORITY. CHINESE TRANSLATIONS. Each party executing this
Agreement represents and warrants to the other parties that it has been duly
authorized under applicable law to execute and deliver this Agreement. This
Agreement will be translated into the Chinese language by us and approved and
signed by Distributor within five days after receipt and this Agreement will
become effective upon the signing of the Chinese translation. For the
avoidance of doubt, the Chinese translation will not change the substantive
meanings of this Agreement.

CALYPTE BIOMEDICAL CORPORATION:            BEIJING HUA AI SCIENCE AND TECHNOLGY
                                           DEVELOPMENT CO. LTD:

By: /s/ Nancy E. Katz                      By: /s/ Zheng Xiwen
   ---------------------------                --------------------------------
Name: Nancy E. Katz                        Name: Zheng Xiwen
                                              --------------------------------
Title: President                           Title: Director
                                              --------------------------------
Date signed:  5/16/00                      Date signed: May 16, 2000

PERFORMANCE OF DISTRIBUTOR GUARANTEED:

NATIONAL CENTER FOR AIDS PREVENTION AND CONTROL:

By: /s/ Zheng Xiwen
   ---------------------------
Name: Zheng Xiwen
     -------------------------
Title: Deputy Director (Executive)
      ------------------------
Date signed: May 16, 2000
            ------------------

THE CHINESE ACADEMY OF PREVENTIVE MEDICINE

By: /s/ Wang Kean
   ---------------------------
Name: Wang Kean
     -------------------------
Title: President
      ------------------------
Date signed: May 16, 2000
            ------------------

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       13
<PAGE>

                                EXHIBIT A

               CALYPTE PRODUCTS AND PRICES TO DISTRIBUTOR

[*]

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       14
<PAGE>

                                    EXHIBIT B

                    DISTRIBUTOR MINIMUM PURCHASE REQUIREMENTS

[*]

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION.  CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT
TO THE OMITTED PORTIONS.

                                       15

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