Exhibit 10.76


                             SECURED PROMISSORY NOTE


$629,672.09                                                 Berkeley, California
                                                            June 30, 2000


         1. OBLIGATION. Howard B. Urnovitz (the "OBLIGOR"), for value received,
hereby promises to pay to the order of Calypte Biomedical Corporation (the
"PAYEE"), on December 31, 2000, in lawful money of the United States of America
at the address of the Payee set forth below, (a) the principal sum of Six
Hundred Twenty-Nine Thousand Six Hundred Seventy-Two Dollars and Nine Cents
($629,672.09), which principal sum includes (i) Five Hundred Twenty-Five
Thousand Seven Hundred Seventy-Seven Dollars and Fifty-Five Cents ($525,777.55)
as the principal amount, as agreed by the Obligor and Payee hereby to have been
due as of the issuance date thereof, notwithstanding any other figure therein to
the contrary, under Obligor's Secured Promissory Note to the Payee dated
November 13, 1998 (the "1998 NOTE"), plus (ii) One Hundred Three Thousand Eight
Hundred Ninety-Four Dollars and Fifty-Four Cents ($103,894.54) of interest on
the 1998 Note accrued to date, none of which principal or interest has been paid
to the date hereof, together with (b) interest on the unpaid principal hereof
from the date hereof until paid in full, at an annual rate equal to the Prime
Rate, as hereinafter defined. The "PRIME RATE" will mean the prime rate as
published from time to time in the WALL STREET JOURNAL. Accrued interest will be
payable on payment of principal, and will continue to accrue until all principal
and accrued interest will be paid in full. Any payment of less than the total
principal amount and all accrued interest hereunder will be credited first to
accrued but unpaid interest and the balance to principal, and interest will
cease to accrue on the amount of principal so paid. Interest will be computed on
the basis of a year of 365 days for the actual number of days elapsed. This Note
may be prepaid, in whole or in part, at any time without premium or penalty. The
Obligor will, on or before August 31, 2000, sell as much of the shares of stock
of the Payee as he owns as he lawfully can sell, having net proceeds to the
Obligor, after taxes and brokerage fees and other customary costs of sale, up to
the amount owed by the Obligor hereunder, and will pay such proceeds to the
Payee, immediately upon the Obligor's receipt thereof, as a payment hereunder to
reduce the Obligor's obligations hereunder; provided that the Obligor will not
be required to sell any shares on or before such date at a price of less than
Three Dollars and Fifty Cents ($3.50). Any such shares so sold by the Obligor
will be deemed released, upon such sale, from the security interest of the Payee
granted herein. The Obligor will be responsible for and will timely pay when due
all taxes, brokerage fees and other customary costs of sale legally required to
be paid by the Payee as a result of such sale of his shares and will hold the
Payee harmless against payment thereof.

         2. EFFECT OF THIS NOTE UPON 1998 NOTE; CERTAIN WAIVERS BY PAYEE. This
Note is being issued by the Obligor to the Payee as a replacement for the 1998
Note, and upon such issuance hereof, the 1998 Note is cancelled and of no
further force and effect. The Payee hereby waives (a) the failure of the Obligor
to timely pay the 1998 Note when due, and (b) any failure of the Obligor to
maintain the level of Collateral required thereunder, provided that such waivers
are given only for such specific failures and are not given for any other
failure of Obligor either retroactively or prospectively.


         3. GRANT OF SECURITY INTEREST IN THE COLLATERAL. To secure the prompt
and punctual payment of and performance of all obligations hereunder, the
Obligor hereby grants to the Payee a continuing security interest in and lien on
all of the Obligor's right, title and interest in all the shares of capital
stock held of record or beneficially by the Obligor, and in all options held by
the Obligor to purchase capital stock of, (a) the Payee, and (b) to the extent
any such shares are held by the Obligor from time to time prior to payment in
full of this Note by the Obligor, and if permitted by the Board of Directors of
the relevant following-named corporations, of (i) Chronix Corporation and (ii)
Pepgen Corporation, whether now owned or hereafter acquired, and all proceeds
and products thereof (collectively, the "COLLATERAL"). The Obligor agrees that
the Payee may imprint a legend on the certificates evidencing all shares of
stock that are part of the Collateral in order to properly refer to this Note
therein and the security interest of the Payee therein. Upon payment in full of
all



amounts due under this Note, the Payee will remove such legends and will
promptly return to the Obligor all Collateral then held by the Payee.

     4.   CERTAIN COVENANTS OF THE OBLIGOR. The Obligor agrees and covenants
that:

          (a)  The Obligor will execute and deliver such documents, and take
such other actions, as the Payee deems necessary to create, perfect and continue
the perfection of the security interest in the Collateral contemplated hereby.
The Obligor will, as soon as possible after the date hereof, deliver to the
Payee, to the attention of its Chief Executive Officer, to hold as Collateral
pursuant to this Note, all shares of stock of the Company, and, to the extent
then held by the Obligor, of Chronix Corporation and Pepgen Corporation held by
the Obligor.

          (b)  The Obligor will pay all expenses, including attorneys fees,
reasonably incurred by the Payee in the preservation, realization, enforcement
or exercise of any of the Payee's rights under this Note.

          (c)  If while this Note is outstanding the aggregate fair market value
of the Collateral is less than two hundred percent (200%) of the then-current
outstanding balance of this Note, the Obligor will, unless waived by the Payee
on a case-by-case basis in writing no more frequently than monthly, by the end
of each month in which such Collateral maintenance condition is not met, which
waiver will be entirely within the discretion of Payee, increase the Collateral
by (i) such number of shares of capital stock in the Payee, and/or of Chronix
Corporation and/or of Pepgen Corporation, to the extent that the Obligor then
holds any such shares, and/or by (ii) unexercised options to purchase shares of
capital stock of the Payee, and/or of Chronix Corporation and/or of Pepgen
Corporation, in each case to the extent that the Obligor then holds any such
unexercised options, such that the total aggregate fair market value of the
Collateral, less any exercise price for any such options, is not less than two
hundred percent (200%) of the then-outstanding balance of this Note.

     5.   EVENTS OF DEFAULT. If the Obligor fails to pay when due and payable
any principal or interest due hereunder within five (5) business days (defined
as a day when national banks in California are open for business) after the date
scheduled for payment thereof (an "EVENT OF DEFAULT") then, at the expiration of
such five-day period, or at any time thereafter, the Payee will have all rights,
privileges, powers and remedies provided by law and by this Note, which rights,
privileges, powers and remedies will be cumulative, and no single or partial
exercise of any of them will preclude the further or other exercise of the same
or any of them.

     6.   APPOINTMENT OF PAYEE AS ATTORNEY-IN-FACT. The Obligor hereby appoints
the Payee the attorney-in-fact of the Obligor to prepare, sign and file or
record, for the Obligor in the Obligor's name, any financing statements,
applications for registration and like papers and to take any other action
deemed by the Payee to be reasonably necessary or desirable in order to perfect
the security interest of the Payee hereunder in the Collateral.



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     7.   MISCELLANEOUS.

          (a)  BINDING NATURE. This Note will be binding upon and inure to the
benefit of the Payee and its successors and assigns, and will be binding upon
and inure to the benefit of the Obligor and the Obligor's successors and
assigns, heirs, administrators and executors.

          (b)  CERTAIN WAIVERS BY OBLIGOR. Presentment, protest, notice of
protest, notice of dishonor, and notice of nonpayment are waived with respect to
any proceeds to which the Payee is entitled hereunder and any rights to direct
the application of payments for security for indebtedness of the Obligor
hereunder, and any right to require proceedings against others or to require
exhaustion of security, are waived by the Obligor.

          (c)  GOVERNING LAW. This Note is being delivered in and will be
construed in accordance with the internal laws of the State of California. The
Obligor hereby submits to the exclusive jurisdiction of and venue in the
Superior Court of the State of California for the County of San Francisco for
purposes of any legal action, and agrees that service upon the Obligor in any
such action may be made by first class certified mail to the Obligor's address
as it appears below.

          (d)  NOTICES. Notices and communications required or permitted
hereunder will be in writing and will be deemed to have been given upon delivery
if personally delivered or upon deposit if deposited in the United States mail
for mailing by certified mail, postage prepaid, and addressed as follows:

          If to the Payee:

                Calypte Biomedical Corporation
                Attention: Chief Financial Officer
                1265 Harbor Bay Parkway
                Alameda, California 94502

          If to the Obligor:

                Howard B. Urnovitz, Ph.D.
                1440 Fourth Street
                Berkeley, California 94710

     Each of the above addressees may change its address for purposes of this
Paragraph 7(d) by giving to the other addressee notice in conformance with this
Paragraph 7(d) of such new address.

                                    Obligor:

                                    /s/ Howard B. Urnovitz
                                    ----------------------------
                                    HOWARD B. URNOVITZ

ACKNOWLEDGED AS TO PRINCIPAL AMOUNT OF 1998 NOTE AND INTEREST ACCRUED THEREON TO
THE DATE HEREOF, AS STATED HEREIN, AND AS TO WAIVERS HEREIN BY CALYPTE
BIOMEDICAL CORPORATION:

CALYPTE BIOMEDICAL CORPORATION

By:  /s/ Nancy E. Katz
   ------------------------------
Name:  Nancy E. Katz
     ----------------------------
Title:  CEO, President, CFO
      ---------------------------

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