EXHIBIT C

NEITHER  THESE  SECURITIES  NOR THE  SECURITIES  ISSUABLE UPON EXERCISE OF THESE
SECURITIES HAVE BEEN  REGISTERED WITH THE SECURITIES AND EXCHANGE  COMMISSION OR
THE  SECURITIES  COMMISSION  OF ANY STATE IN  RELIANCE  UPON AN  EXEMPTION  FROM
REGISTRATION  UNDER THE  SECURITIES  ACT OF 1933,  AS AMENDED  (THE  "SECURITIES
ACT"),  AND,  ACCORDINGLY,  MAY NOT BE OFFERED  OR SOLD  EXCEPT  PURSUANT  TO AN
EFFECTIVE  REGISTRATION  STATEMENT  UNDER THE  SECURITIES  ACT OR PURSUANT TO AN
AVAILABLE  EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE  REGISTRATION
REQUIREMENTS  OF THE  SECURITIES  ACT AND IN ACCORDANCE  WITH  APPLICABLE  STATE
SECURITIES  LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO
SUCH  EFFECT,  THE  SUBSTANCE  OF WHICH SHALL BE  REASONABLY  ACCEPTABLE  TO THE
COMPANY.  THESE  SECURITIES AND THE  SECURITIES  ISSUABLE UPON EXERCISE OF THESE
SECURITIES MAY BE PLEDGED IN CONNECTION  WITH A BONA FIDE MARGIN ACCOUNT SECURED
BY SUCH SECURITIES.

                         CALYPTE BIOMEDICAL CORPORATION

                                SERIES A WARRANT

Warrant No. [  ]                             Original Issue Date:  April 4, 2005

      CALYPTE BIOMEDICAL  CORPORATION,  a Delaware  corporation (the "COMPANY"),
hereby  certifies that, for value received,  [ ] or its registered  assigns (the
"HOLDER"), is entitled to purchase from the Company up to a total of [ ]1 shares
of Common Stock (each such share,  a "WARRANT  SHARE" and all such  shares,  the
"WARRANT  SHARES"),  at any time and from  time to time  from and  after the six
month  anniversary of the Original Issue Date and through and including April 3,
2010 (the "EXPIRATION DATE"), and subject to the following terms and conditions:

      1.  Definitions.  As used in this Warrant,  the following terms shall have
the respective  definitions set forth in this Section 1. Capitalized  terms that
are used and not  defined  in this  Warrant  that are  defined  in the  Purchase
Agreement (as defined below) shall have the respective  definitions set forth in
the Purchase Agreement.

      "BUSINESS DAY" means any day except Saturday, Sunday and any day that is a
federal  legal  holiday  in  the  United  States  or  a  day  on  which  banking
institutions in the State of New York are authorized or required by law or other
government action to close.


---------------------
1 A number of shares  equal to 100% of the number of shares into which the Notes
may be converted.

<PAGE>

      "COMMON  STOCK" means the common stock of the Company,  par value $.03 per
share,  and any  securities  into  which  such  common  stock may  hereafter  be
reclassified.

      "EXERCISE PRICE" means the greater of (i) $0.325, subject to adjustment in
accordance  with Section 9, and (ii) the last trade price of the Common Stock on
the Closing Date or the date of the Purchase Agreement (whichever is greater).

      "FUNDAMENTAL  TRANSACTION"  means any of the  following:  (1) the  Company
effects any merger or  consolidation of the Company with or into another Person,
(2) the Company  effects any sale of all or  substantially  all of its assets in
one or a series of related transactions,  (3) any tender offer or exchange offer
(whether  by the  Company or  another  Person) is  completed  pursuant  to which
holders of Common  Stock are  permitted  to tender or exchange  their shares for
other   securities,   cash  or  property,   or  (4)  the  Company   effects  any
reclassification  of the Common Stock or any compulsory share exchange  pursuant
to which the Common Stock is  effectively  converted into or exchanged for other
securities, cash or property.

      "ORIGINAL ISSUE DATE" means the Original Issue Date first set forth on the
first page of this Warrant.

      "NEW YORK COURTS" means the state and federal  courts  sitting in the City
of New York, Borough of Manhattan.

      "PURCHASE AGREEMENT" means the  Purchase Agreement,  dated  April 4, 2005,
to which the Company and the original Holder are parties.

      "TRADING  DAY"  means (i) a day on which the  Common  Stock is traded on a
Trading Market (other than the OTC Bulletin Board),  or (ii) if the Common Stock
is not listed on a Trading Market (other than the OTC Bulletin  Board), a day on
which the Common Stock is traded in the over-the-counter  market, as reported by
the OTC  Bulletin  Board,  or (iii) if the  Common  Stock is not  quoted  on any
Trading   Market,   a  day  on  which  the   Common   Stock  is  quoted  in  the
over-the-counter   market  as  reported  by  the   National   Quotation   Bureau
Incorporated (or any similar  organization or agency succeeding to its functions
of reporting prices);  provided,  that in the event that the Common Stock is not
listed or quoted as set forth in (i),  (ii) and (iii)  hereof,  then Trading Day
shall mean a Business Day.

      2.  Registration of Warrant.  The Company shall register this Warrant upon
records  to be  maintained  by  the  Company  for  that  purpose  (the  "WARRANT
REGISTER"),  in the name of the  record  Holder  hereof  from time to time.  The
Company may deem and treat the registered Holder of this Warrant as the absolute
owner hereof for the purpose of any exercise  hereof or any  distribution to the
Holder, and for all other purposes, absent actual notice to the contrary.

      3.  Registration of Transfers.  The Company shall register the transfer of
any portion of this  Warrant in the Warrant  Register,  upon  surrender  of this
Warrant,  with the Form of Assignment attached hereto duly completed and signed,
to the Company at its address  specified  herein.  Upon any such registration or
transfer,  a new Warrant to purchase Common Stock, in substantially  the form of
this Warrant (any such new Warrant, a "NEW Warrant"),  evidencing the portion of
this Warrant so transferred  shall be issued to the transferee and a New Warrant
evidencing  the remaining  portion of this Warrant not so  transferred,  if any,
shall be issued to the transferring Holder. The acceptance of the New Warrant by
the transferee  thereof shall be deemed the acceptance by such transferee of all
of the rights and obligations of a holder of a Warrant.

                                       2
<PAGE>

      4. Exercise and Duration of Warrants. This Warrant shall be exercisable by
the  registered  Holder at any time and from time to time from and after the six
month  anniversary  of the  Original  Issue Date and through and  including  the
Expiration  Date.  At 6:30 p.m.  California  time on the  Expiration  Date,  the
portion of this Warrant not exercised prior thereto shall be and become void and
of no value.  The  Company  may not call or redeem any  portion of this  Warrant
without the prior written consent of the affected Holder.

      5. Delivery of Warrant Shares.

            (a) To effect exercises hereunder,  the Holder shall not be required
to  physically  surrender  this  Warrant  unless the  aggregate  Warrant  Shares
represented  by this Warrant is being  exercised.  Upon delivery of the Exercise
Notice (in the form attached  hereto) to the Company (with the attached  Warrant
Shares Exercise Log) at its address for notice set forth herein and upon payment
of the Exercise Price multiplied by the number of Warrant Shares that the Holder
intends to purchase hereunder, the Company shall promptly (but in no event later
than three  Trading Days after the Date of Exercise (as defined  herein))  issue
and deliver to the Holder,  a certificate  for the Warrant Shares  issuable upon
such exercise, which, unless otherwise required by the Purchase Agreement, shall
be free of restrictive  legends.  The Company shall,  upon request of the Holder
and subsequent to the date on which a registration statement covering the resale
of the Warrant Shares has been declared effective by the Securities and Exchange
Commission,  use its reasonable best efforts to deliver Warrant Shares hereunder
electronically  through the Depository Trust Corporation or another  established
clearing corporation performing similar functions, if available, provided, that,
the Company may,  but will not be required to change its  transfer  agent if its
current transfer agent cannot deliver Warrant Shares electronically  through the
Depository Trust  Corporation.  A "DATE OF EXERCISE" means the date on which the
Holder shall have  delivered to the Company:  (i) the Exercise  Notice (with the
Warrant  Exercise Log attached to it),  appropriately  completed and duly signed
and (ii) if such Holder is not utilizing the cashless  exercise  provisions  set
forth in this Warrant,  payment of the Exercise  Price for the number of Warrant
Shares so indicated by the Holder to be purchased.

            (b) If by the third Trading Day after a Date of Exercise the Company
fails to deliver the required  number of Warrant  Shares in the manner  required
pursuant to Section  5(a),  then the Holder will have the right to rescind  such
exercise.

            (c) If by the third Trading Day after a Date of Exercise the Company
fails to deliver the required  number of Warrant  Shares in the manner  required
pursuant to Section  5(a),  and if after such third Trading Day and prior to the
receipt  of such  Warrant  Shares,  the  Holder  purchases  (in an  open  market
transaction or otherwise) shares of Common Stock to deliver in satisfaction of a
sale by the Holder of the Warrant Shares which the Holder anticipated  receiving
upon such exercise (a  "BUY-IN"),  then the Company shall (1) pay in cash to the
Holder the amount by which (x) the  Holder's  total  purchase  price  (including
brokerage  commissions,  if any) for the  shares  of Common  Stock so  purchased
exceeds (y) the amount  obtained by multiplying (A) the number of Warrant Shares
that the Company was  required to deliver to the Holder in  connection  with the
exercise at issue by (B) the  closing bid price of the Common  Stock on the Date
of Exercise and (2) at the option of the Holder, either reinstate the portion of
the Warrant and equivalent  number of Warrant Shares for which such exercise was
not  honored or deliver to the Holder the number of shares of Common  Stock that
would have been issued had the Company  timely  complied  with its  exercise and
delivery  obligations  hereunder.  The Holder shall provide the Company  written
notice indicating the amounts payable to the Holder in respect of the Buy-In.

                                       3
<PAGE>

            (d) The Company's obligations to issue and deliver Warrant Shares in
accordance with the terms hereof are absolute and unconditional, irrespective of
any action or inaction by the Holder to enforce the same,  any waiver or consent
with respect to any provision  hereof,  the recovery of any judgment against any
Person  or  any  action  to  enforce  the  same,  or any  setoff,  counterclaim,
recoupment,  limitation or  termination,  or any breach or alleged breach by the
Holder or any other Person of any  obligation to the Company or any violation or
alleged violation of law by the Holder or any other Person,  and irrespective of
any other  circumstance  which  might  otherwise  limit such  obligation  of the
Company to the Holder in connection with the issuance of Warrant Shares. Nothing
herein shall limit a Holder's right to pursue any other remedies available to it
hereunder,  at law or in  equity  including,  without  limitation,  a decree  of
specific  performance  and/or  injunctive  relief with respect to the  Company's
failure to timely deliver certificates representing Warrant Shares upon exercise
of the Warrant as required pursuant to the terms hereof.

      6. Charges,  Taxes and Expenses.  Issuance and delivery of Warrant  Shares
upon exercise of this Warrant shall be made without charge to the Holder for any
issue or transfer tax,  withholding tax,  transfer agent fee or other incidental
tax or expense in respect of the  issuance  of such  certificates,  all of which
taxes and expenses  shall be paid by the Company;  provided,  however,  that the
Company  shall not be required to pay any tax which may be payable in respect of
any transfer involved in the registration of any certificates for Warrant Shares
or  Warrants  in a name  other  than that of the  Holder.  The  Holder  shall be
responsible for all other tax liability that may arise as a result of holding or
transferring this Warrant or receiving Warrant Shares upon exercise hereof.

      7. Replacement of Warrant.  If this Warrant is mutilated,  lost, stolen or
destroyed,  the  Company  shall  issue or cause to be  issued  in  exchange  and
substitution for and upon  cancellation  hereof,  or in lieu of and substitution
for this Warrant,  a New Warrant,  but only upon receipt of evidence  reasonably
satisfactory to the Company of such loss, theft or destruction and customary and
reasonable  indemnity  (which shall not include a surety  bond),  if  requested.
Applicants  for a New Warrant  under such  circumstances  shall also comply with
such other  reasonable  regulations and procedures and pay such other reasonable
third-party costs as the Company may prescribe. If a New Warrant is requested as
a result of a mutilation  of this  Warrant,  then the Holder shall  deliver such
mutilated  Warrant to the  Company as a  condition  precedent  to the  Company's
obligation to issue the New Warrant.

      8.  Reservation of Warrant Shares.  The Company  covenants that it will at
all times reserve and keep  available out of the aggregate of its authorized but
unissued  and  otherwise  unreserved  Common  Stock,  solely for the  purpose of
enabling  it to issue  Warrant  Shares upon  exercise of this  Warrant as herein
provided,  the number of Warrant Shares which are then issuable and  deliverable

                                       4
<PAGE>

upon the exercise of this entire  Warrant,  free from  preemptive  rights or any
other  contingent  purchase rights of Persons other than the Holder (taking into
account the  adjustments and  restrictions of Section 9). The Company  covenants
that all Warrant Shares so issuable and deliverable shall, upon issuance and the
payment of the applicable Exercise Price in accordance with the terms hereof, be
duly and validly authorized, issued and fully paid and nonassessable.

      9. Certain  Adjustments.  The Exercise  Price and number of Warrant Shares
issuable upon  exercise of this Warrant are subject to  adjustment  from time to
time as set forth in this Section 9.

            (a) Stock  Dividends and Splits.  If the Company,  at any time while
this Warrant is  outstanding,  (i) pays a stock  dividend on its Common Stock or
otherwise  makes a distribution on any class of capital stock that is payable in
shares of Common Stock, (ii) subdivides  outstanding shares of Common Stock into
a larger number of shares, or (iii) combines  outstanding shares of Common Stock
into a smaller number of shares, then in each such case the Exercise Price shall
be multiplied by a fraction of which the numerator shall be the number of shares
of Common  Stock  outstanding  immediately  before  such  event and of which the
denominator   shall  be  the  number  of  shares  of  Common  Stock  outstanding
immediately after such event. Any adjustment made pursuant to clause (i) of this
paragraph  shall  become  effective  immediately  after the record  date for the
determination of stockholders entitled to receive such dividend or distribution,
and any  adjustment  pursuant  to clause (ii) or (iii) of this  paragraph  shall
become  effective  immediately  after the effective date of such  subdivision or
combination.

            (b) Fundamental Transactions.  If, at any time while this Warrant is
outstanding there is a Fundamental  Transaction,  then the Holder shall have the
right thereafter to receive,  upon exercise of this Warrant, the same amount and
kind of  securities,  cash or property as it would have been entitled to receive
upon the occurrence of such Fundamental  Transaction if it had been, immediately
prior to such  Fundamental  Transaction,  the  holder of the  number of  Warrant
Shares then  issuable  upon  exercise in full of this  Warrant  (the  "ALTERNATE
CONSIDERATION").  For purposes of any such exercise,  the  determination  of the
Exercise  Price  shall be  appropriately  adjusted  to  apply to such  Alternate
Consideration based on the amount of Alternate Consideration issuable in respect
of one share of Common Stock in such  Fundamental  Transaction,  and the Company
shall  apportion  the  Exercise  Price among the  Alternate  Consideration  in a
reasonable manner  reflecting the relative value of any different  components of
the Alternate Consideration.  If holders of Common Stock are given any choice as
to the securities, cash or property to be received in a Fundamental Transaction,
then the Holder shall be given the same choice as to the Alternate Consideration
it  receives  upon any  exercise  of this  Warrant  following  such  Fundamental
Transaction. At the Holder's option and request, any successor to the Company or
surviving entity in such Fundamental  Transaction shall, either (1) issue to the
Holder a new warrant  substantially  in the form of this Warrant and  consistent
with the foregoing  provisions and evidencing the Holder's right to purchase the
Alternate  Consideration for the aggregate Exercise Price upon exercise thereof,
or (2)  purchase the Warrant  from the Holder for a purchase  price,  payable in
cash within five Trading Days after such request (or, if later, on the effective
date of the  Fundamental  Transaction),  equal to the Black Scholes value of the
remaining  unexercised portion of this Warrant on the date of such request.  The
terms of any agreement  pursuant to which a Fundamental  Transaction is effected


                                       5
<PAGE>

shall include terms  requiring any such successor or surviving  entity to comply
with the  provisions of this paragraph (c) and insuring that the Warrant (or any
such  replacement  security)  will be  similarly  adjusted  upon any  subsequent
transaction analogous to a Fundamental Transaction.

            (c) Subsequent Equity Sales.

                  (i) If the Company or any subsidiary  thereof,  as applicable,
at any time prior to the one year  anniversary of the Original Issue Date, shall
issue shares of Common Stock or Common Stock Equivalents entitling any Person to
acquire  shares of Common  Stock,  at a price per share  less than the  Exercise
Price (if the holder of the Common  Stock or Common Stock  Equivalent  so issued
shall at any time,  whether by operation of purchase  price  adjustments,  reset
provisions,  floating conversion,  exercise or exchange prices or otherwise,  or
due to warrants,  options or rights issued in connection with such issuance,  be
entitled  to receive  shares of Common  Stock at a price less than the  Exercise
Price, such issuance shall be deemed to have occurred for less than the Exercise
Price),  then,  the  Exercise  Price shall be reduced to equal such lower price.
Such  adjustment  shall be made  whenever  such  Common  Stock or  Common  Stock
Equivalents are issued. The Company shall notify the Holder in writing, no later
than the Trading Day  following the issuance of any Common Stock or Common Stock
Equivalent subject to this section,  indicating therein the applicable  issuance
price, or of applicable reset price, exchange price,  conversion price and other
pricing terms.

                  (ii) For  purposes  of this  subsection  9(c),  the  following
subsections (c)(ii)(l) to (c)(ii)(6) shall also be applicable:

                    (1)  Issuance of Rights or Options.  In case at any time the
Company shall in any manner grant (directly and not by assumption in a merger or
otherwise) any warrants or other rights to subscribe for or to purchase,  or any
options for the purchase of,  Common Stock or any stock or security  convertible
into or exchangeable  for Common Stock (such  warrants,  rights or options being
called "OPTIONS" and such convertible or exchangeable  stock or securities being
called  "CONVERTIBLE  SECURITIES")  whether or not such  Options or the right to
convert or exchange any such Convertible Securities are immediately exercisable,
and the price per share for which Common Stock is issuable  upon the exercise of
such Options or upon the conversion or exchange of such  Convertible  Securities
(determined  by dividing (i) the sum (which sum shall  constitute the applicable
consideration)  of (x) the total amount,  if any,  received or receivable by the
Company  as  consideration  for the  granting  of  such  Options,  plus  (y) the
aggregate  amount of  additional  consideration  payable to the Company upon the
exercise of all such Options, plus (z), in the case of such Options which relate
to Convertible Securities, the aggregate amount of additional consideration,  if
any, payable upon the issue or sale of such Convertible  Securities and upon the
conversion or exchange  thereof,  by (ii) the total maximum  number of shares of
Common Stock  issuable upon the exercise of such Options or upon the  conversion
or exchange of all such  Convertible  Securities  issuable  upon the exercise of
such Options) shall be less than the Exercise Price in effect  immediately prior
to the time of the granting of such Options,  then the total number of shares of
Common Stock  issuable  upon the exercise of such Options or upon  conversion or
exchange of the total amount of such  Convertible  Securities  issuable upon the
exercise of such Options  shall be deemed to have been issued for such price per
share  as of the  date of  granting  of such  Options  or the  issuance  of such

                                       6
<PAGE>

Convertible  Securities  and thereafter  shall be deemed to be  outstanding  for
purposes of  adjusting  the  Exercise  Price.  Except as  otherwise  provided in
subsection  9(c)(ii)(3),  no adjustment of the Exercise Price shall be made upon
the actual issue of such Common  Stock or of such  Convertible  Securities  upon
exercise  of such  Options or upon the actual  issue of such  Common  Stock upon
conversion or exchange of such Convertible Securities.

                    (2) Issuance of Convertible Securities.  In case the Company
shall in any  manner  issue  (directly  and not by  assumption  in a  merger  or
otherwise)  or sell any  Convertible  Securities,  whether  or not the rights to
exchange or convert any such Convertible Securities are immediately exercisable,
and the price per share for which Common Stock is issuable upon such  conversion
or exchange  (determined by dividing (i) the sum (which sum shall constitute the
applicable  consideration) of (x) the total amount received or receivable by the
Company as consideration  for the issue or sale of such Convertible  Securities,
plus (y) the aggregate  amount of additional  consideration,  if any, payable to
the Company upon the conversion or exchange thereof, by (ii) the total number of
shares of Common  Stock  issuable  upon the  conversion  or exchange of all such
Convertible  Securities)  shall  be less  than  the  Exercise  Price  in  effect
immediately  prior to the time of such  issue or sale,  then the  total  maximum
number of shares of Common Stock  issuable  upon  conversion  or exchange of all
such  Convertible  Securities shall be deemed to have been issued for such price
per share as of the date of the issue or sale of such Convertible Securities and
thereafter  shall be deemed to be  outstanding  for  purposes of  adjusting  the
Exercise  Price,  provided  that (a) except as otherwise  provided in subsection
9(c)(ii)(3),  no adjustment of the Exercise  Price shall be made upon the actual
issuance of such Common Stock upon  conversion  or exchange of such  Convertible
Securities and (b) no further  adjustment of the Exercise Price shall be made by
reason of the  issue or sale of  Convertible  Securities  upon  exercise  of any
Options to purchase any such Convertible Securities for which adjustments of the
Exercise  Price have been made  pursuant to the other  provisions  of subsection
9(c).

                    (3)  Change in Option  Price or  Conversion  Rate.  Upon the
happening of any of the following events, namely, if the purchase price provided
for in any Option referred to in subsection  9(c)(ii)(l)  hereof, the additional
consideration,   if  any,  payable  upon  the  conversion  or  exchange  of  any
Convertible Securities referred to in subsections 9(c)(ii)(l) or 9(c)(ii)(2), or
the rate at which Convertible Securities referred to in subsections  9(c)(ii)(l)
or  9(c)(ii)(2)  are  convertible  into or  exchangeable  for Common Stock shall
change at any time (including, but not limited to, changes under or by reason of
provisions  designed to protect against dilution),  the Exercise Price in effect
at the time of such event shall  forthwith be readjusted  to the Exercise  Price
which  would have been in effect at such time had such  Options  or  Convertible
Securities  still   outstanding   provided  for  such  changed  purchase  price,
additional  consideration  or  conversion  rate, as the case may be, at the time
initially  granted,  issued or sold. On the  termination of any Option for which
any adjustment was made pursuant to this subsection 9(c) or any right to convert
or exchange Convertible Securities for which any adjustment was made pursuant to
this  subsection  9(c)  (including  without  limitation  upon the  redemption or
purchase for consideration of such Convertible  Securities by the Company),  the
Exercise  Price  then in effect  hereunder  shall  forthwith  be  changed to the
Exercise  Price which would have been in effect at the time of such  termination
had such Option or Convertible Securities, to the extent outstanding immediately
prior to such termination, never been issued.

                                       7
<PAGE>

                    (4)  Stock  Dividends.  Subject  to the  provisions  of this
Section  9(c),  in case the Company  shall  declare a dividend or make any other
distribution upon any stock of the Company (other than the Common Stock) payable
in Common  Stock,  Options or  Convertible  Securities,  then any Common  Stock,
Options or Convertible  Securities,  as the case may be,  issuable in payment of
such  dividend  or  distribution  shall be deemed  to have  been  issued or sold
without consideration.

                    (5)  Consideration  for Stock.  In case any shares of Common
Stock,  Options or Convertible  Securities shall be issued or sold for cash, the
consideration received therefor shall be deemed to be the net amount received by
the Company therefor,  after deduction therefrom of any expenses incurred or any
underwriting  commissions  or  concessions  paid or  allowed  by the  Company in
connection therewith. In case any shares of Common Stock, Options or Convertible
Securities  shall be issued or sold for a  consideration  other than  cash,  the
amount of the  consideration  other than cash  received by the Company  shall be
deemed to be the fair value of such consideration as determined in good faith by
the Board of Directors of the Company,  after deduction of any expenses incurred
or any underwriting commissions or concessions paid or allowed by the Company in
connection therewith. In case any Options shall be issued in connection with the
issue and sale of other  securities  of the  Company,  together  comprising  one
integral  transaction  in which no specific  consideration  is allocated to such
Options by the parties thereto, such Options shall be deemed to have been issued
for such  consideration as determined in good faith by the Board of Directors of
the Company. If Common Stock, Options or Convertible  Securities shall be issued
or  sold  by  the  Company  and,  in  connection  therewith,  other  Options  or
Convertible   Securities  (the  "ADDITIONAL   RIGHTS")  are  issued,   then  the
consideration  received or deemed to be received by the Company shall be reduced
by the fair  market  value of the  Additional  Rights (as  determined  using the
Black-Scholes  option pricing model or another method  mutually agreed to by the
Company and the Holder).  The Board of Directors  of the Company  shall  respond
promptly,  in writing,  to an inquiry by the Holders as to the fair market value
of the  Additional  Rights.  In the  event  that the Board of  Directors  of the
Company and the  Holders  are unable to agree upon the fair market  value of the
Additional  Rights,  the  Company  and  the  Holders  shall  jointly  select  an
appraiser,  who is experienced  in such matters.  The decision of such appraiser
shall be final and conclusive,  and the cost of such appraiser shall be borne by
the Company provided that in the event that the valuation determined by Board of
Directors is within ten percent (10%) the valuation determined by the appraiser,
such costs shall be borne evenly by the Company and the Holder.

                    (6) Record Date.  In case the Company shall take a record of
the holders of its Common Stock for the purpose of entitling them (i) to receive
a dividend or other distribution payable in Common Stock, Options or Convertible
Securities  or (ii) to  subscribe  for or  purchase  Common  Stock,  Options  or
Convertible Securities,  then such record date shall be deemed to be the date of
the issue or sale of the shares of Common  Stock  deemed to have been  issued or
sold  upon  the  declaration  of such  dividend  or the  making  of  such  other
distribution  or the  date of the  granting  of such  right of  subscription  or
purchase, as the case may be.

                  (iii)  Notwithstanding  the foregoing,  no adjustment  will be
made under this paragraph (c) in respect of: (1) the issuance of securities upon
the exercise or conversion of any Common Stock Equivalents issued by the Company
prior to the Original Issue Date of this Warrant (but this subsection (c) will


                                       8
<PAGE>

apply to any amendments,  modifications, and reissuances thereof and as a result
of any  changes,  resets  or  adjustments  to a  Conversion  or  Exchange  Price
thereunder  whether  or  not  as a  result  of any  amendment,  modification  or
reissuance),  or (2) the  grant of  options  or  warrants,  or the  issuance  of
additional  securities,  under any duly authorized  Company stock option,  stock
incentive plan, restricted stock plan or stock purchase plan in existence on the
Closing Date or thereafter  approved by the stockholders of the Company,  or (3)
shares  of Common  Stock or  Common  Stock  Equivalents  issued to  consultants,
employees,  officers or  directors  of the Company,  as  compensation  for their
services to the Company or any of its direct or indirect  Subsidiaries  pursuant
to arrangements approved by the Board of Directors of the Company and consistent
with past  practice,  or (4) the  issuance  of the  Securities  pursuant  to the
Transaction  Documents,  or (5) up to 250,000  shares of Common  Stock or Common
Stock Equivalents  issuable in connection with an equipment financing by Vencore
Solutions,  LLC, or (6) the issuance of Common Stock to  Logisticorp,  Inc., and
Southwest Resource  Preservation,  Inc., or their successors and assigns,  based
upon the issuance and conversion of outstanding convertible debentures, with the
issuance of said Common  Stock not to exceed  700,000  shares,  or (7) shares of
Common Stock issued as  consideration  for the acquisition of another company or
business  in which the  shareholders  of the  Company  do not have an  ownership
interest,  which  acquisition has been approved by the Board of Directors of the
Company, or (8) pursuant to the Anti-Dilution  Entitlements and New Entitlements
(each as defined  in the  Amendment),  or (9)  shares of Common  Stock or Common
Stock Equivalents issued in connection with Strategic Transactions.

                  (iv) The adjustments that would arise under this paragraph (c)
shall only take effect from such time as the  Company has  obtained  Stockholder
Approval;  and if such  Stockholder  Approval is obtained,  then the adjustments
that would have occurred under this paragraph (c) for issuance prior to the date
of  such  Stockholder  Approval  shall  take  effect  as of  the  date  of  such
Stockholder Approval.

            (d) Number of Warrant Shares.  Simultaneously with any adjustment to
the Exercise  Price  pursuant to this Section 9(a), the number of Warrant Shares
that may be  purchased  upon  exercise of this  Warrant  shall be  increased  or
decreased proportionately,  so that after such adjustment the aggregate Exercise
Price payable  hereunder for the adjusted  number of Warrant Shares shall be the
same as the  aggregate  Exercise  Price  in  effect  immediately  prior  to such
adjustment.

            (e)  Calculations.  All  calculations  under this Section 9 shall be
made to the nearest cent or the nearest 1/100th of a share,  as applicable.  The
number of shares of Common Stock outstanding at any given time shall not include
shares owned or held by or for the account of the Company,  and the  disposition
of any such shares shall be considered an issue or sale of Common Stock.

            (f) Notice of  Adjustments.  Upon the occurrence of each  adjustment
pursuant to this  Section 9, the Company at its expense  will  promptly  compute
such  adjustment  in  accordance  with the terms of this  Warrant  and prepare a
certificate setting forth such adjustment, including a statement of the adjusted
Exercise Price and adjusted number or type of Warrant Shares or other securities
issuable  upon  exercise  of  this  Warrant  (as  applicable),   describing  the
transactions  giving  rise to such  adjustments  and showing in detail the facts
upon which such  adjustment  is based.  Upon written  request,  the Company will
promptly  deliver  a copy of each  such  certificate  to the  Holder  and to the
Company's Transfer Agent.

                                       9
<PAGE>

            (g)  Notice of  Corporate  Events.  If the  Company  (i)  declares a
dividend or any other  distribution  of cash,  securities  or other  property in
respect of its Common Stock, including without limitation any granting of rights
or warrants to subscribe for or purchase any capital stock of the Company or any
Subsidiary, (ii) authorizes or approves, enters into any agreement contemplating
or  solicits  stockholder  approval  for any  Fundamental  Transaction  or (iii)
authorizes the voluntary  dissolution,  liquidation or winding up of the affairs
of the Company, then the Company shall deliver to the Holder a notice describing
the material  terms and conditions of such  transaction  (but only to the extent
such disclosure would not result in the  dissemination  of material,  non-public
information  to the  Holder) at least 10 calendar  days prior to the  applicable
record or  effective  date on which a Person  would need to hold Common Stock in
order to  participate  in or vote  with  respect  to such  transaction,  and the
Company  will take all steps  reasonably  necessary  in order to insure that the
Holder is given the practical opportunity to exercise this Warrant prior to such
time so as to participate in or vote with respect to such transaction; provided,
however, that the failure to deliver such notice or any defect therein shall not
affect the  validity of the  corporate  action  required to be described in such
notice.

      10.  Payment of Exercise  Price.  The Holder may pay the Exercise Price in
one of the following manners:

            (a) Cash  Exercise.  The Holder may  deliver  immediately  available
funds; or

            (b) Cashless Exercise.  If an Exercise Notice is delivered at a time
when a registration statement permitting the Holder to resell the Warrant Shares
is not then  effective  or the  prospectus  forming a part  thereof  is not then
available  to the Holder for the resale of the Warrant  Shares,  then the Holder
may notify the Company in an Exercise Notice of its election to utilize cashless
exercise,  in which  event the  Company  shall issue to the Holder the number of
Warrant Shares determined as follows:

               X = Y [(A-B)/A]

      where:

               X = the number of Warrant Shares to be issued to the Holder.

               Y  =  the  number  of  Warrant  Shares  with
               respect  to  which  this  Warrant  is  being
               exercised.

               A = the  average of the  closing  prices for
               the five Trading Days  immediately  prior to
               (but not including) the Exercise Date.

               B = the Exercise Price.

For purposes of Rule 144  promulgated  under the Securities Act, it is intended,
understood  and  acknowledged  that the  Warrant  Shares  issued  in a  cashless
exercise  transaction  shall be deemed to have been acquired by the Holder,  and
the holding period for the Warrant Shares shall be deemed to have commenced,  on
the Original Issue Date.

                                       10
<PAGE>

      11. Limitations on Exercise.

            (a)  Notwithstanding  anything to the contrary contained herein, the
number of Warrant Shares that may be acquired by the Holder upon any exercise of
this  Warrant (or  otherwise in respect  hereof)  shall be limited to the extent
necessary to insure that, following such exercise (or other issuance), the total
number of shares of Common Stock then beneficially  owned by such Holder and its
Affiliates  and any other  Persons  whose  beneficial  ownership of Common Stock
would be  aggregated  with the  Holder's  for  purposes of Section  13(d) of the
Exchange  Act,  does not  exceed  9.999%  of  the total  number  of  issued  and
outstanding  shares of Common  Stock  (including  for such purpose the shares of
Common  Stock  issuable  upon  such  exercise).  For such  purposes,  beneficial
ownership  shall be determined in accordance  with Section 13(d) of the Exchange
Act and the rules and regulations promulgated  thereunder.  This provision shall
not  restrict the number of shares of Common Stock which a Holder may receive or
beneficially  own in  order to  determine  the  amount  of  securities  or other
consideration  that  such  Holder  may  receive  in the  event of a  Fundamental
Transaction as contemplated in Section 9 of this Warrant.  This  restriction may
not be waived.(2)

            (b) Notwithstanding anything to the contrary in this Warrant, if the
Company has not previously obtained Stockholder  Approval,  then the Company may
not issue  shares  of  Common  Stock in  excess  of the  Issuable  Maximum  upon
exercises of this  Warrant.  The  "Issuable  Maximum"  means,  as of any date, a
number of shares of Common Stock equal to  34,224,397.  Each  Investor  shall be
entitled to a portion of the Issuable Maximum equal to the quotient  obtained by
dividing:  (x) the principal amount of Notes issued and sold to such Investor on
the  Original  Issue  Date by (y) the  aggregate  principal  amount of all Notes
issued and sold by the Company on the Original Issue Date. If any Investor shall
no longer hold Warrants,  then such Investor's remaining portion of the Issuable
Maximum shall be allocated pro-rata among the remaining Investors, giving effect
to the  Company's  desire  to  allocate  this  limitation  among  the  class  of
securities known as the Warrants. If on any Exercise Date, or at such time as an
Investor  shall notify the Company  that the  condition  in (A)  following  this
clause shall be in effect:  (A) the  aggregate  number of shares of Common Stock
that  would  then be  issuable  upon  exercise  in full of all then  outstanding
Warrants  would  exceed the Issuable  Maximum on such date,  and (B) the Company
shall not have previously obtained the vote of shareholders,  as may be required
by the applicable  rules and  regulations of the American Stock Exchange (or any
successor  entity or any other Trading Market on which the Company's  securities
then  trade),  applicable  to approve the  issuance of shares of Common Stock in
excess of the Issuable  Maximum  pursuant to the terms hereof (the  "STOCKHOLDER
APPROVAL"),  then, the Company shall issue to the Investor a number of shares of
Common  Stock  such that the  total  number of  shares  issued  pursuant  to the
Purchase  Agreement  is equal to the Issuable  Maximum and,  with respect to the
remainder of the  aggregate  Warrants  then held by the  Investors  for which an
exercise  would result in an issuance of shares of Common Stock in excess of the
Issuable  Maximum,  the  Company  must use its best  efforts  to seek and obtain
Stockholder  Approval as soon as  possible,  but in any event not later than the
90th day following  such Exercise Date or the date of such request.  The Company
and the Holder  understand and agree that Warrant Shares issued to and then held
by the Holder as a result of exercises of Warrants shall not be entitled to cast
votes on any resolution to obtain Stockholder Approval pursuant hereto.

-----------------------
(2) This provision will not be in the Marr warrant.


                                       11
<PAGE>

      12. No Fractional  Shares.  No fractional shares of Warrant Shares will be
issued  in  connection  with  any  exercise  of  this  Warrant.  In  lieu of any
fractional shares which would, otherwise be issuable, the Company shall pay cash
equal to the product of such  fraction  multiplied  by the closing  price of one
Warrant  Share as  reported  by the  applicable  Trading  Market  on the date of
exercise.

      13.  Notices.  Any and all notices or other  communications  or deliveries
hereunder  (including,  without  limitation,  any Exercise  Notice)  shall be in
writing and shall be deemed given and  effective on the earliest of (i) the date
of  transmission,  if such notice or communication is delivered via facsimile at
the facsimile number specified in this Section prior to 6:30 p.m. (New York City
time)  on  a  Trading  Day,  (ii)  the  next  Trading  Day  after  the  date  of
transmission,  if such notice or communication is delivered via facsimile at the
facsimile number specified in this Section on a day that is not a Trading Day or
later than 6:30 p.m. (New York City time) on any Trading Day,  (iii) the Trading
Day following the date of mailing,  if sent by nationally  recognized  overnight
courier service, or (iv) upon actual receipt by the party to whom such notice is
required to be given. The addresses for such communications  shall be: (i) if to
the Company, to Calypte Biomedical Corporation, Attn: President, or to Facsimile
No.:  (925)  730-0146 (or such other  address as the Company  shall  indicate in
writing in  accordance  with this  Section),  or (ii) if to the  Holder,  to the
address or  facsimile  number  appearing  on the Warrant  Register or such other
address  or  facsimile  number as the  Holder  may  provide  to the  Company  in
accordance with this Section.

      14.  Warrant  Agent.  The Company  shall serve as warrant agent under this
Warrant.  Upon 10 days'  notice to the  Holder,  the  Company  may appoint a new
warrant agent.  Any corporation  into which the Company or any new warrant agent
may be merged or any corporation  resulting from any  consolidation to which the
Company or any new warrant  agent shall be a party or any  corporation  to which
the  Company  or  any  new  warrant  agent  transfers  substantially  all of its
corporate trust or shareholders  services  business shall be a successor warrant
agent under this Warrant  without any further act.  Any such  successor  warrant
agent shall  promptly  cause  notice of its  succession  as warrant  agent to be
mailed (by first class mail, postage prepaid) to the Holder at the Holder's last
address as shown on the Warrant Register.

      15. Miscellaneous.

            (a) This Warrant shall be binding on and inure to the benefit of the
parties  hereto and their  respective  successors  and  assigns.  Subject to the
preceding  sentence,  nothing in this Warrant  shall be construed to give to any
Person  other than the  Company  and the Holder  any legal or  equitable  right,
remedy or cause of action under this  Warrant.  This Warrant may be amended only
in  writing  signed by the  Company  and the  Holder  and their  successors  and
assigns.

                                       12
<PAGE>

            (b) All questions concerning the construction, validity, enforcement
and  interpretation  of this  Warrant  shall be  governed by and  construed  and
enforced in  accordance  with the internal laws of the State of New York (except
for matters governed by corporate law in the State of Delaware),  without regard
to the principles of conflicts of law thereof.  Each party agrees that all legal
proceedings  concerning  the  interpretations,  enforcement  and defense of this
Warrant  and  the  transactions  herein  contemplated  ("PROCEEDINGS")  (whether
brought  against  a party  hereto or its  respective  Affiliates,  employees  or
agents) shall be commenced exclusively in the New York Courts. Each party hereto
hereby irrevocably submits to the exclusive  jurisdiction of the New York Courts
for the adjudication of any dispute hereunder or in connection  herewith or with
any transaction  contemplated hereby or discussed herein, and hereby irrevocably
waives,  and  agrees not to assert in any  Proceeding,  any claim that it is not
personally  subject  to the  jurisdiction  of any New York  Court,  or that such
Proceeding has been commenced in an improper or inconvenient  forum.  Each party
hereto hereby  irrevocably  waives  personal  service of process and consents to
process  being  served in any such  Proceeding  by  mailing a copy  thereof  via
registered or certified  mail or overnight  delivery (with evidence of delivery)
to such party at the address in effect for notices to it under this  Warrant and
agrees that such service shall constitute good and sufficient service of process
and notice thereof. Nothing contained herein shall be deemed to limit in any way
any right to serve  process in any manner  permitted  by law.  Each party hereto
hereby  irrevocably  waives,  to the fullest extent permitted by applicable law,
any and all right to trial by jury in any  legal  proceeding  arising  out of or
relating to this  Warrant or the  transactions  contemplated  hereby.  If either
party shall  commence a Proceeding  to enforce any  provisions  of this Warrant,
then the prevailing  party in such  Proceeding  shall be reimbursed by the other
party for its  attorney's  fees and other costs and expenses  incurred  with the
investigation, preparation and prosecution of such Proceeding.

            (c) The headings herein are for convenience  only, do not constitute
a part of this  Warrant  and shall  not be deemed to limit or affect  any of the
provisions hereof.

            (d) In case any one or more of the  provisions of this Warrant shall
be invalid or unenforceable in any respect,  the validity and  enforceability of
the  remaining  terms and  provisions  of this  Warrant  shall not in any way be
affected or impaired thereby and the parties will attempt in good faith to agree
upon a valid and enforceable provision which shall be a commercially  reasonable
substitute  therefor,  and upon so agreeing,  shall  incorporate such substitute
provision in this Warrant.

            (e) Prior to exercise of this Warrant,  the Holder hereof shall not,
by reason of being a Holder,  be  entitled to any rights of a  stockholder  with
respect to the Warrant Shares.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK,
                             SIGNATURE PAGE FOLLOWS]


                                       13
<PAGE>

      IN  WITNESS  WHEREOF,  the  Company  has  caused  this  Warrant to be duly
executed by its authorized officer as of the date first indicated above.

                                    CALYPTE BIOMEDICAL CORPORATION

                                    By:
                                       ----------------------------
                                       Name:  Richard D. Brounstein
                                       Title: EVP and CFO






                                       14
<PAGE>


                                 EXERCISE NOTICE
                         CALYPTE BIOMEDICAL CORPORATION
                           WARRANT DATED APRIL 4, 2005

The  undersigned  Holder  hereby  irrevocably  elects to purchase  _____________
shares of Common Stock  pursuant to the above  referenced  Warrant.  Capitalized
terms used herein and not  otherwise  defined have the  respective  meanings set
forth in the Warrant.

(1)  The   undersigned   Holder   hereby   exercises   its  right  to   purchase
_________________ Warrant Shares pursuant to the Warrant.

(2) The Holder  intends  that  payment of the  Exercise  Price  shall be made as
(check one):

                     ____"Cash Exercise" under Section 10

                     ____"Cashless Exercise" under Section 10

(3) If the holder has elected a Cash  Exercise,  the holder shall pay the sum of
$____________ to the Company in accordance with the terms of the Warrant.

(4) Pursuant to this  Exercise  Notice,  the Company shall deliver to the holder
_______________ Warrant Shares in accordance with the terms of the Warrant.

(5) By its delivery of this Exercise  Notice,  the  undersigned  represents  and
warrants to the Company that in giving effect to the exercise  evidenced  hereby
the Holder will not beneficially own in excess of the number of shares of Common
Stock  (determined in accordance  with Section 13(d) of the Securities  Exchange
Act of 1934)  permitted  to be owned under  Section 11 of this  Warrant to which
this notice relates.

Dated:                      ,                Name of Holder:
       ---------------------  -------

                                             (Print)
                                                    ----------------------------

                                             By:
                                                 -------------------------------
                                             Name:
                                                  ------------------------------
                                             Title:
                                                   -----------------------------

                                             (Signature   must  conform  in  all
                                             respects  to  name   of  holder  as
                                             specified  on  the   face   of  the
                                             Warrant)


                                       15
<PAGE>

<TABLE>
<CAPTION>

                           Warrant Shares Exercise Log

----------------------------- ----------------------------- ---------------------------------- ---------------------
<S>                          <C>                           <C>                                <C>
Date                          Number of Warrant Shares      Number of Warrant Shares           Number of Warrant
                              Available to be Exercised     Exercised                          Shares  Remaining to
                                                                                               be Exercised
----------------------------- ----------------------------- ---------------------------------- ---------------------









----------------------------- ----------------------------- ---------------------------------- ---------------------

</TABLE>


                                       16
<PAGE>

                         CALYPTE BIOMEDICAL CORPORATION
                     WARRANT ORIGINALLY ISSUED APRIL 4, 2005
                                 WARRANT NO. [ ]


                               FORM OF ASSIGNMENT


      [To be completed and signed only upon transfer of Warrant]

      FOR VALUE RECEIVED,  the undersigned  hereby sells,  assigns and transfers
unto    ________________________________    the   right   represented   by   the
above-captioned Warrant to purchase ____________ shares of Common Stock to which
such Warrant  relates and appoints  ________________  attorney to transfer  said
right on the  books of the  Company  with  full  power  of  substitution  in the
premises.

Dated:   _______________, ____

                                     -------------------------------------------
                                    (Signature  must  conform in all respects to
                                     name of holder as specified on  the face of
                                     the Warrant)



                                     -------------------------------------------
                                     Address of Transferee

                                     -------------------------------------------

                                     -------------------------------------------


In the presence of:


--------------------------


                                       17