**AMENDMENT
      TO SECURED 8% CONVERTIBLE PROMISSORY NOTES**









THIS
      AMENDMENT (this " **Amendment** ")
      to
      Secured 8% Convertible Promissory Notes (each, a “ **Note** ,”
and
      collectively, the " **Notes** ")
      is
      made as of March 21, 2007, by and between Calypte Biomedical Corporation, a
      Delaware corporation (the " **Company** "),
      and
      Marr Technologies BV, a limited liability company established in the Netherlands
      (the “ **Investor** ”).
      If
      there is any inconsistency between the terms of this Amendment and any other
      agreement referenced herein, the terms of this Amendment will
      govern.




WHEREAS,
      the Company and the Investor are parties to (i) the Securities Purchase
      Agreement dated May 28, 2004 (the “ **Securities
      Purchase Agreement** ”)
      among
      the Company and the investors signatory thereto ( “ **Investors
      I** ”),
      pursuant to which the Company issued and sold to Investors I, and Investors
      I
      purchased from the Company, certain shares and warrants pursuant to the terms
      set forth in the Securities Purchase Agreement, (ii) the Amendment to Securities
      Purchase Agreement dated April 4, 2005 (the “ **Amendment
      to Securities Purchase Agreement** ”)
      among
      the Company and Investors I, pursuant to which Investors I received certain
      anti-dilution entitlements and new entitlements, including, without limitation,
      certain warrants pursuant to the terms set forth in the Amendment to Securities
      Purchase Agreement, (iii) the 2005 Credit Facility Agreement dated April 4,
      2005, as amended November 30, 2005, February 22, 2006, July 6, 2006, December
      22, 2006 and February 6, 2007 (collectively, the “ **Credit
      Facility** ”),
      between the Company and the Investor pursuant to which the Investor has loaned
      money to the Company and the Company has issued to the Investor various secured
      promissory notes (the “ **Secured
      Notes** ”),
      (iv)
      the Purchase Agreement dated as of April 4, 2005 (the **"Purchase
      Agreement"** )
      among
      the Company and the investors signatory thereto ( “ **Investors
      II** ”),
      pursuant to which the Company issued and sold to Investors II, and Investors
      II
      purchased from the Company, certain secured 8% convertible promissory notes,
      which included the Notes, Series A warrants and Series B warrants pursuant
      to
      the terms set forth in the Purchase Agreement, and (v) the letter agreement
      dated July 7, 2006 (the “ **Letter
      Agreement** ”)
      between the Company and the Investor, pursuant to which the 2004 Warrants and
      the 2004 Amendment Warrants were amended to lower their exercise price from
      $0.45 to $0.15 for a period of time commencing through and including July 21,
      2006, after which time the exercise price reverted back to $0.45 and to issue
      to
      the Investor an additional warrant equal to 50% of the aggregate amount of
      the
      2005 Amendment Warrants exercised before July 21, 2006 (the “ **2006**  **Additional
      Warrant** ”);




WHEREAS,
      the parties now desire to change the maturity date (the “ **Maturity
      Date** ”)
      of the
      Notes issued by the Company to the Investor pursuant to the Purchase Agreement,
      which consists of the initial Note in the principal amount of $2,800,000 and
      the
      Notes issued to the Investor on a quarterly basis as interest payments, in
      accordance with the provisions set forth in Section 15(f) of the Notes and
      Section 6.4 of the Purchase Agreement;




WHEREAS,
      in consideration of the foregoing, the Company agrees to lower the exercise
      price of the Investor’s currently outstanding warrants, which consist of
      8,482,292 shares of the Company’s common stock pursuant to the 2006 Additional
      Warrant (the “ **Warrant
      Shares** ”),
      as
      follows: the Exercise Price of 40% of the Warrants Shares, equaling 3,392,917
      Warrant Shares, will be lowered to $0.03 per Warrant Share and the Exercise
      Price of 60% of the Warrant Shares, equaling 5,089,375 Warrant Shares, will
      be
      lowered to $0.10 per Warrant Share, and to change the expiration date of the
      warrants to coincide with the change of the Maturity Date of the Notes;
      and







WHEREAS,
      the parties agree to amend and modify the 2006 Additional Warrant to delete
      the
      provision of piggyback registration rights from the 2006 Additional Warrant.




NOW,
      THEREFORE, for good and valuable consideration, the receipt and sufficiency
      of
      which are hereby acknowledged, the Company and the Investor agree as
      follows:




1.  All
      references in the Notes to the due date of “April 3, 2007” are hereby amended to
“April 3, 2009.”




2.  The
      2006
      Additional Warrant is hereby amended to lower the exercise prices as more
      specifically set forth in the amended warrants, which are attached hereto as Exhibit
      A-1 ,
      and Exhibit
      A-2 and to
      delete the provision of piggyback registration rights from the 2006 Additional
      Warrant.




3.  The
      Expiration Date (as defined in the 2006 Additional Warrant) is hereby amended
      to
      April 3, 2009.




4.  This
      Amendment shall not be binding upon the Company or the Investor unless and
      until
      SF Capital Partners Ltd. (“ **SF** ”)
      has
      executed and delivered to the Company an Amendment to Secured 8% Convertible
      Promissory Notes in which SF agrees to change the maturity date to April 3,
      2009
      of all notes issued to it by the Company in connection with that certain
      Purchase Agreement dated April 4, 2005 (including, without limitation, any
      notes
      issued to it for the payment of interest due on the notes).




5.  Except
      for the amendments provided for herein, the Notes and the 2006 Additional
      Warrant shall remain unchanged and in full force and effect.




6.  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.




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




[ **Signature
      Pages Follow** ]







[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:


Richard
      D. Brounstein


Executive
      Vice President















[SIGNATURE
      PAGE FOR THE INVESTOR]




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




Marr
                  Technologies BVName
                  of InvestorBy:SignatureIts:Title