AMENDMENT
      TO REGISTRATION RIGHTS AGREEMENT

     

    This
      Amendment to Registration Rights Agreement (this “Amendment”)
      is made
      and entered into as of July 7, 2007, by and among Calypte Biomedical
      Corporation, a Delaware corporation (the “Company”),
      and
      the investors signatory hereto (each an “Investor”
      and
      collectively, the “Investors”).
      Unless
      otherwise defined herein, all capitalized terms used herein shall have the
      meanings given to them in the Registration Rights Agreement referred to
      below.

     

    WHEREAS,
      the Company and the Investors are parties to a Registration Rights Agreement
      dated as of March 28, 2007 (the "Registration
      Rights Agreement");
      

     

    WHEREAS,
      based on comments the Company received from the Securities and Exchange
      Commission, the parties desire to amend the Registration Rights Agreement to
      delete the requirement that the Registration Statement cover the resale of
      the
      Warrant Shares.

     

    WHEREAS,
      the parties agree to amend and modify the Registration Rights Agreement to
      provide for certain other modifications and amendments agreed to by the parties
      in accordance with the provisions set forth in Section 6(e) of the Registration
      Rights Agreement.

     

    NOW,
      THEREFORE, for good and valuable consideration, the receipt and sufficiency
      of
      which are hereby acknowledged, the Company and each Investor, severally and
      not
      jointly, agree as follows:

     

    
      	
            	1.	
              The
                definition of “Notes” in Section 1 of the Registration Rights Agreement is
                hereby deleted in its entirety.

            


    

     

    
      	
            	2.	
              The
                definition of “Registrable Shares” in Section 1 of the Registration Rights
                Agreement is hereby amended and restated to read in its entirety
                as
                follows:

            


    

     

    “‘Registrable
      Securities’
      means
      the Shares issued or issuable pursuant to the Subscription Agreement, together
      with any securities issued or issuable upon any stock split, dividend or other
      distribution, recapitalization or similar event.”

     

    
      	
            	3.	
              Section
                2(a) of the Registration Rights Agreement is hereby amended and restated
                to read in its entirety as follows:

            


    

     

    “(a)
       On
      or
      prior to each Filing Date, the Company shall prepare and file with the
      Commission a Registration Statement covering the resale of all Registrable
      Securities not already covered by an existing and effective Registration
      Statement for an offering to be made on a continuous basis pursuant to Rule
      415.
      The Registration Statement shall be on Form SB-2 or Form S-3 (except if the
      Company is not then eligible to register for resale the Registrable Securities
      on Form SB-2 or Form S-3, in which case such registration shall be on
      another appropriate form for such purpose) and shall contain (except if
      otherwise required pursuant to written comments received from the Commission
      upon a review of such Registration Statement) the “Plan of Distribution”
attached hereto as Annex
      A.
      The
      Company shall use its best efforts to cause each Registration Statement to
      be
      declared effective under the Securities Act within 120 days following the
      Closing Date and shall use its best efforts to keep each Registration Statement
      continuously effective under the Securities Act until the second year after
      the
      date that the Registration Statement is declared effective by the Commission
      or
      such earlier date when all Registrable Securities covered by the Registration
      Statement have been sold or may be sold without volume restrictions pursuant
      to
      Rule 144(k) as determined by the counsel to the Company pursuant to a written
      opinion letter to such effect, addressed and acceptable to the Company's
      transfer agent and the affected Investors (the “Effectiveness
      Period”).
      The
      initial Registration Statement shall include a number of Registrable Securities
      equal to 100,000,000, the number of Shares issued at the Closing.” 

     

    
      
         

      

      
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            	4.	
              Section
                2(c) of the Registration Rights Agreement is hereby amended and restated
                to read in its entirety as follows:

            


    

     

    “(c)
       If
      a
      Registration Statement is not filed on or prior to its Filing Date (such failure
      being referred to as an “Event,”
      and the
      date on which such Event occurs being referred to as “Event
      Date”),
      then
      in addition to any other rights the Investors may have under applicable law
      or
      at equity: (x) on the Event Date the Company shall pay to each Investor an
      amount, as partial liquidated damages and not as a penalty, equal to 1.0% of
      the
      amount of such Investor’s investment, such payment in cash; and (y) beginning
      with the one (1) month anniversary following each such Event Date, and on each
      monthly anniversary thereafter (if the applicable Event shall not have been
      cured by such date) until the applicable Event is cured, the Company shall
      pay
      to each Investor an amount, as partial liquidated damages and not as a penalty,
      equal to 2.0% of the aggregate amount of such Investor’s investment, such
      payment being in cash. The partial liquidated damages pursuant to the terms
      hereof shall apply on a daily pro-rata basis for any portion of a month prior
      to
      the cure of an Event, including in the case of the first Event Date.”


    


    
      	
            	5.	
              Section
                6(e) of the Registration Rights Agreement is hereby amended and restated
                to read in its entirety as follows:

            


    

     

    “(e)
       Amendments
      and Waivers.
      The
      provisions of this Agreement, including the provisions of this sentence, may
      not
      be amended, modified or supplemented, and waivers or consents to departures
      from
      the provisions hereof may not be given, unless the same shall be in writing
      and
      signed by the Company and the Investors holding at least a majority of the
      Registrable Shares held by the Investors. Notwithstanding the foregoing, a
      waiver or consent to depart from the provisions hereof with respect to a matter
      that relates exclusively to the rights of certain Investors and that does not
      directly or indirectly affect the rights of other Investors may be given by
      Investors of at least a majority of the Registrable Securities to which such
      waiver or consent relates, provided,
      that
      the provisions of this sentence may not be amended, modified, or supplemented
      except in accordance with the provisions of the immediately preceding
      sentence.”

     

    
      
         

      

      
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            	6.	
              Except
                for the amendments provided for herein, the Registration Rights Agreement
                shall remain unchanged and in full force and effect.
                

            


    

     

    
      	
            	7.	
              This
                Amendment may be executed in counterparts, each of which shall be
                deemed
                to be an original, but which together shall be deemed to be one and
                the
                same instrument.

            


    

     

    
      	
            	8.	
              This
                Amendment shall be governed by and construed in accordance with the
                laws
                of the State of Oregon without giving effect to the conflicts of
                law
                principles thereof.

            


    

     

    [REMAINDER
      OF PAGE INTENTIONALLY LEFT BLANK


    [SIGNATURE
      PAGE FOR THE COMPANY] 

     

    
      
         

      

      
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      [SIGNATURE
        PAGE FOR THE COMPANY] 

       

    

    IN
      WITNESS WHEREOF,
      each of
      the parties hereto has caused a counterpart of this Amendment to be duly
      executed and delivered as of the date first above written.

     

    
      	 	 	 
	 	
              Calypte
                Biomedical Corporation 

            
	 
 	 
 	 
 
	
            	By:  	
            
	 	
              

              Signature

            


    

    
    

     

      	 	 	 
	: 	Its:	
            
	 	
              
Title 


    

     

    
      
         

      

      
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    [SIGNATURE
      PAGE FOR INVESTORS]

     

    IN
      WITNESS WHEREOF,
      each of
      the parties hereto has caused a counterpart of this Amendment Agreement to
      be
      duly executed and delivered as of the date first above written.

    
      	 	 	 	 
	
              David
                Khidasheli

            	 	 	
              Mohamed
                Yousif Ahmed Saleh Sulaiman

            
	
              

              Name
                of Investor 

            	 	 	
              

              Name
                of Investor 

            
	 

              

              Signature

            	 	 	 

              

              Signature

            
	 	 	 	 


    

    
      	 	 	 	 
	
              Mohamed
                Ahmed

            	 	 	
              Ahmed
                Abdulla Deemas al Swaidi

            
	
              

              Name
                of Investor 

            	 	 	
              

              Name
                of Investor 

            
	 

              

              Signature

            	 	 	 

              

              Signature

            


    

     

    
      
         

      

      
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