**AMENDMENT
        TO SECURED 8% CONVERTIBLE PROMISSORY NOTES**
  
  THIS
        AMENDMENT (this " **Amendment** ")
        to
        Secured 8% Convertible Promissory Notes (the " **Notes** ")
        is
        made as of March 21, 2007, by and between Calypte Biomedical Corporation,
        a
        Delaware corporation (the " **Company** "),
        and
        Morningtown Limited, a limited liability company established in Mauritius
        (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 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 (iv) 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
        in the initial principal amount of $450,000 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
        1,087,500 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 435,000
        Warrant Shares, will be lowered to $0.03 per Warrant Share and the Exercise
        Price of 60% of the Warrant Shares, equaling 652,500 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.  Except
        for the amendments provided for herein, the Notes and the 2006 Additional
        Warrant shall remain unchanged and in full force and effect.
  4.  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.
  5.  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.




Morningtown
                  LimitedName
                  of InvestorBy:SignatureIts:Title