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                                                               Exhibit 10.83

                       [CARTER-WALLACE, INC. LETTERHEAD]



                                                   December 12, 2000


Ms. Nancy E. Katz
President & Chief Operating Officer
Calypte Biomedical Corporation
1265 Harbor Bay Parkway
Alameda, CA 94502


     RE:  DISTRIBUTION AGREEMENT DATED SEPTEMBER 9, 1999 BETWEEN CALYPTE
          BIOMEDICAL CORPORATION AND CARTER-WALLACE, INC. (THE "AGREEMENT")


This will serve to confirm the agreement between Calypte Biomedical
Corporation ("Calypte") and Carter-Wallace, Inc. ("CW") with respect to the
grant to Calypte of an option (as defined below) to terminate the captioned
Agreement on the following terms:

     1.   Calypte is hereby granted the option to terminate the Agreement on
          [*] (the "Option").

     2.   Calypte may exercise the Option, at its sole discretion, at any
          time prior to midnight, San Francisco time, on [*] by giving written
          notice via facsimile or overnight delivery to CW.

     3.   Should Calypte exercise the Option, it will on [*] purchase from CW
          at CW's cost all remaining CW inventory of products covered by the
          Agreement (the "Products") in CW's possession on [*].

     4.   Calypte will pay to CW on the dates indicated below the following
          amounts as consideration for the grant of the Option by CW.

          [*]

[*]  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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     5.   Commencing on the date of execution of this letter agreement,
          Calypte will have a co-exclusive right to sell the urine-based
          Products to non-CW customers in market areas listed on Schedule A
          hereto.

     6.   In consideration for the grant of the Option by CW, if Calypte
          exercises the Option and CW is able to convert any four of the
          potential customers listed on Schedule B hereto to use the Products
          on or prior to [*], Calypte will make an additional payment of [*]
          to CW on [*].

     7.   Should Calypte exercise the Option, CW shall collaborate with
          Calypte to effect on [*] a smooth transition of the business
          covered by the Agreement. This will include supplying Calypte with
          a copy of the customer list for the Products by [*] and supplying
          to Calypte the remaining useable selling materials for the Products
          in CW's possession no later than [*].

     8.   If Calypte exercises the Option, effective [*] Calypte will assume
          all responsibility and liability for the Products covered by the
          Agreement, including without limitation, the responsibility for
          providing technical service for the Products, even if the Products
          had previously been sold by CW.

     9.   Except as indicated below, neither party shall make an announcement
          concerning this letter agreement or Calypte's exercise of the
          Option until [*]. If Calypte elects to exercise the Option prior to
          [*] any such announcement will be subject to the review and the
          written approval of both parties. Calypte and CW each reserve the
          right to make such disclosures in such manner and at such time as
          each should reasonably determine, upon advice of counsel, are
          required by law.


                                         Very truly yours,

                                         CARTER-WALLACE, INC.

                                         /s/ RALPH LEVINE
                                         -------------------------------------
                                         Ralph Levine
                                         President and Chief Operating Officer

ACCEPTED AND AGREED TO:

CALYPTE BIOMEDICAL CORPORATION


By: /s/ NANCY E. KATZ
   ------------------------------

Date:    12/20/00
     ----------------------------



[*]  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.

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                                Calypte Biomedical
                                    Schedule 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.

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                                Calypte Biomedical
                                    Schedule B
                                       [*]



























[*]  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.