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                                                                   EXHIBIT 10.20

                     FIRST AMENDMENT TO RESEARCH AGREEMENT

         This First Amendment to Research Agreement (hereafter "Amendment") is
made and effective by and between NEW YORK UNIVERSITY, a corporation organized
and existing under the laws of the State of New York, having a place of business
at 70 Washington Square South, New York, New York 10012 (hereafter "NYU"); and
Calypte Biomedical Corporation, a corporation organized and existing under the
laws of California, having a place of business at 1440 Fourth Street, Berkeley,
California 94710 hereafter "CORPORATION").

                                  WITNESSETH:

         WHEREAS, CORPORATION and NYU entered into a certain research agreement
made and effective as of August 1 2, 1 993 (the "Research Agreement"), pursuant
to which, inter alia, CORPORATION undertook to fund certain research relating
to the detection of antibodies to human immunodeficiency virus (HIV) in urine
at NYU, and the parties agreed to certain other related matters as specified
herein; and

         WHEREAS, CORPORATION and NYU wish to modify certain terms and
conditions of the Agreement as specified herein.

         NOW, THEREFORE, in consideration of the premises and the covenants,
conditions and promises set forth below, the parties hereto hereby agree as
follows:

1 .      Except as expressly provided for herein, all terms and conditions of
         the Research Agreement shall remain in full force and effect.




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2.       Terms which are defined in the Agreement shall have the same meanings
         when used in this Amendment, unless a different definition is given
         herein.

3.       Section 1.h of the Research Agreement shall be, and hereby is, amended
         in its entirety so that, as amended, said Section 1.h. shall read as
         follows:

         h.      "Research Period" shall mean the period commencing on the
                 Effective Date hereof and ending on January 1, 1999; provided,
                 however, if the Exclusivity Period as such term is defined in
                 Section 9.a. of the License Agreement between NYU and
                 CORPORATION having an effective date of August 12, 1993 and
                 amended ___________________________, 1994 is extended to
                 January 1, 2000 pursuant to the terms of such License
                 Agreement, the termination date of the Research Period shall
                 be January 1, 2000.

4.       Section 4.a. of the Research Agreement shall be, and hereby is,
         amended in its entirety so that, as amended, said Section 4.a. shall
         read as follows:

         a.      As compensation to NYU for work to be performed on the NYU
                 Research Project during the Research Period, subject to any
                 earlier termination of the Research Project pursuant to
                 Section 3.a. hereof, CORPORATION will pay NYU the total sum of

                          ; provided, however, if the Research Period is
                 extended to January 1, 2000, as provided in Section 1.h.
                 above, CORPORATION shall pay NYU the total sum of 

                 Such sums shall be paid in accordance with the




Confidential portion has been omitted and filed separately with the Commission

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                 Schedule of Payments annexed hereto and incorporated herein as
                 Exhibit A-1.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment 
as follows:


NEW YORK UNIVERSITY         CALYPTE BIOMEDICAL CORPORATION



By:  /s/ Isaac T. Kohlberg                    By: /s/
     -----------------------------                ----------------------------
         Isaac T. Kohlberg

        Vice President for
Title:  Industrial Liaison                  Title:  President
       ---------------------------                  --------------------------

Date:   1-11-95                             Date:   1-6-95
       ---------------------------                  --------------------------





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                                 EXHIBIT A-1 to
                   FIRST AMENDMENT TO THE RESEARCH AGREEMENT



                              SCHEDULE OF PAYMENTS





                                                        
         Effective Date                                    

         February 12,   1994                               

         August 12, 1994                                   

         February 12, 1995                                 

         August 12, 1995                                   

         February 12, 1996                                 

         August 1, 1996                                    

         January 1, 1997                                   

         July 1, 1997                                      

         January 1, 1998.                                  

         July 1, 1998                                      


and, if the Research Period ends on January 1, 2000, then

         January 1, 1999                                   

         July 1, 1999                                      



Confidential portion has been omitted
and filed separately with the Commission