<PAGE>

                                                                    Exhibit 4.12

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                               WARRANT AGREEMENT

                                BY AND BETWEEN

                                CARESIDE, INC.

                                      AND

                          H.C. WAINWRIGHT & CO., INC.



                           DATED AS OF MARCH 8, 2000






================================================================================
<PAGE>

                               TABLE OF CONTENTS

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ARTICLE I
     WARRANT CERTIFICATES.....................................................................................       1
     Section 1.1       Forms of Warrant Certificates..........................................................       1
                       -----------------------------
     Section 1.2       Execution of Warrant Certificates......................................................       1
                       ---------------------------------
     Section 1.3       Registration of Warrant Certificates...................................................       2
                       ------------------------------------
     Section 1.4       Exchange and Transfer of Warrant Certificates..........................................       2
                       ---------------------------------------------
     Section 1.5       Lost, Stolen, Mutilated or Destroyed Warrant Certificates..............................       2
                       ---------------------------------------------------------
     Section 1.6       Cancellation of Warrant Certificates...................................................       2
                       ------------------------------------

ARTICLE II
     WARRANT EXERCISE PRICE AND EXERCISE OF WARRANTS..........................................................       3
     Section 2.1       Exercise Price.........................................................................       3
                       --------------
     Section 2.2       Registration of Warrants and Warrant Shares............................................       3
                       -------------------------------------------
     Section 2.3       Procedure for Exercise of Warrants.....................................................       3
                       ----------------------------------
     Section 2.4       Issuance of Common Stock...............................................................       4
                       ------------------------
     Section 2.5       Certificates for Unexercised Warrants..................................................       4
                       -------------------------------------
     Section 2.6       Reservation of Shares..................................................................       5
                       ---------------------
     Section 2.7       No Impairment..........................................................................       5
                       -------------

ARTICLE III
     ADJUSTMENTS AND NOTICE PROVISIONS........................................................................       5
     Section 3.1       Adjustment of Exercise Price...........................................................       5
                       ----------------------------
     Section 3.2       Sales of Certain Securities............................................................       6
                       ---------------------------
     Section 3.3       No Adjustments to Exercise Price.......................................................       8
                       --------------------------------
     Section 3.4       Adjustment of Number of Shares.........................................................       8
                       ------------------------------
     Section 3.5       Reorganizations........................................................................       8
                       ---------------
     Section 3.6       Verification of Computations...........................................................       9
                       ----------------------------
     Section 3.7       Notice of Certain Actions..............................................................       9
                       -------------------------
     Section 3.8       Certificate of Adjustments.............................................................      10
                       --------------------------
     Section 3.9       Warrant Certificate Amendments.........................................................      10
                       ------------------------------
     Section 3.10      Fractional Shares......................................................................      10
                       -----------------

ARTICLE IV
     MISCELLANEOUS............................................................................................      10
     Section 4.1       Payment of Taxes and Charges...........................................................      10
                       ----------------------------
     Section 4.2       Changes to Agreement...................................................................      11
                       --------------------
     Section 4.3       Assignment.............................................................................      11
                       ----------
     Section 4.4       Successor to Company...................................................................      11
                       --------------------
     Section 4.5       Notices................................................................................      11
                       -------
     Section 4.6       Defects in Notice......................................................................      12
                       -----------------
     Section 4.7       Governing Law..........................................................................      12
                       -------------
     Section 4.8       Standing...............................................................................      12
                       --------
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                                      (i)
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     Section 4.9       Headings...............................................................................      12
                       --------
     Section 4.10      Counterparts...........................................................................      13
                       ------------
     Section 4.11      Availability of the Agreement..........................................................      13
                       -----------------------------
     Section 4.12      Entire Agreement.......................................................................      13
                       ----------------

WARRANT AGREEMENT
    COMPANY SIGNATURE PAGE....................................................................................      14

WARRANT AGREEMENT
    PURCHASER SIGNATURE PAGE..................................................................................      15

EXHIBIT A - FORM OF WARRANT CERTIFICATE.......................................................................     A-1
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                                     (ii)
<PAGE>

                               WARRANT AGREEMENT


     THIS WARRANT AGREEMENT (the "Agreement"), dated as of March 8, 2000, is
entered into by and between Careside, Inc., a Delaware corporation (the
"Company"), and H.C. Wainwright & Co., Inc. (the "Purchaser").

                                  WITNESSETH:

     WHEREAS, the Company proposes to sell pursuant to several Securities
Purchase and Subscription Agreements, each dated as of a date in March, 2000
(collectively the "Securities Purchase Agreement"), by and between the Company
and the purchasers named therein, 956,039 shares of common stock, par value
$0.01 per share, of the Company for a purchase of $8.77 per share (the "Common
Stock") in the aggregate principal amount of $8,384,462.03 and contingent
warrants to purchase up to an aggregate of 114,725 shares (subject to
adjustment) of the Common Stock (the "Contingent Warrant"); and

     WHEREAS, the Purchaser has acted as the exclusive placement agent for the
Company in connection with the transactions contemplated by the Securities
Purchase Agreement, and as partial consideration for such services the Company
has issued to Purchaser a warrant (the "Warrant") to acquire 95,604 shares of
Common Stock at an exercise price of $8.77 per share (the Common Stock issuable
upon exercise of the Warrant being referred to herein as the "Warrant Shares")
and contingent warrants to acquire 11,472 additional shares of Common Stock on
the same terms and conditions as the Contingent Warrants;

     NOW, THEREFORE, in consideration of the premises and of the mutual
agreements herein contained, the parties hereto agree as follows:

                                   ARTICLE I
                             WARRANT CERTIFICATES

     Section 1.1  Forms of Warrant Certificates. The warrant certificates (the
                  -----------------------------
"Warrant Certificates") shall be issued substantially in the form of Exhibit A
                                                                     ---------
attached hereto, together with the form of the election to purchase (the
"Election to Purchase") and assignment (the "Assignment") to be attached
thereto, and, in addition, may have such letters, numbers or other marks of
identification or designation and such legends, summaries, or endorsements
stamped, printed, lithographed or engraved thereon as the Company may deem
appropriate and as are not inconsistent with the provisions of this Agreement,
or as, in any particular case, may be required in the opinion of counsel for the
Company, to comply with any law or with any rule or regulation of any regulatory
authority or agency, or to conform to customary usage.

     Section 1.2  Execution of Warrant Certificates. The Warrant Certificates
                  ---------------------------------
shall be executed on behalf of the Company by its Chairman or President or any
Vice President and attested to by its Secretary or Assistant Secretary, either
manually or by facsimile signature printed thereon. In case any authorized
officer of the Company who shall have signed any of the Warrant Certificates
shall cease to be an officer of the Company either before or after delivery
thereof by the Company to any Purchaser, the signature of such person on such
Warrant Certificates shall be valid nevertheless and
<PAGE>

such Warrant Certificates may be issued and delivered to those persons entitled
to receive the Warrants represented thereby with the same force and effect as
though the person who signed such Warrant Certificates had not ceased to be an
officer of the Company.

     Section 1.3  Registration of Warrant Certificates. The Company shall number
                  ------------------------------------
and keep a registry for the Warrant Certificates in a register as they are
needed. The Company may deem and treat the registered holder(s) of the Warrant
Certificates (the "Holders") as the absolute owner(s) thereof for all purposes.

     Section 1.4  Exchange and Transfer of Warrant Certificates. The Warrants
                  ---------------------------------------------
(and any Warrant Shares issued upon exercise of the Warrants) shall bear such
restrictive legend or legends as may be required by the Securities Purchase
Agreement and as may be required by law and shall be transferable only in
accordance with the terms of this Agreement and the Securities Purchase
Agreement.

     The Company may from time to time note the transfer of any outstanding
Warrant Certificates in a warrant register to be maintained by the Company upon
surrender thereof accompanied by a written instrument or instruments of transfer
in form satisfactory to the Company duly executed by the Holder or Holders
thereof or by the duly appointed legal representative thereof or by a duly
authorized attorney. Upon any such registration of transfer, a new Warrant
Certificate shall be issued to the transferee(s).

     Warrant Certificates may be exchanged at the option of the Holder(s)
thereof, when surrendered to the Company at the address set forth in Section 4.5
hereof for another Warrant Certificate or Warrant Certificates of like tenor and
representing in the aggregate a like number of Warrant Shares: provided that the
                                                               --------
Company shall not be required to issue any Warrant Certificate representing any
fractional Warrant Shares.

     Section 1.5  Lost, Stolen, Mutilated or Destroyed Warrant Certificates.
                  ---------------------------------------------------------
If any Warrant Certificate shall be mutilated, lost, stolen or destroyed, the
Company shall issue, execute and deliver, in exchange and substitution for and
upon cancellation of a mutilated Warrant Certificate, or in lieu of or in
substitution for a lost, stolen or destroyed Warrant Certificate, a new Warrant
Certificate representing an equivalent number of Warrants or Warrant Shares. If
required by the Company, the Holder of the mutilated, lost, stolen or destroyed
Warrant Certificate must provide indemnity sufficient to protect the Company
from any loss which it may suffer if the Warrant Certificate is replaced. Any
such new Warrant Certificate shall constitute an original contractual obligation
of the Company, whether or not the allegedly lost, stolen, mutilated or
destroyed Warrant Certificate shall be at any time enforceable by anyone.

     Section 1.6  Cancellation of Warrant Certificates. Any Warrant Certificate
                  ------------------------------------
surrendered upon the exercise of Warrants or for exchange or transfer, or
purchased or otherwise acquired by the Company, shall be canceled and shall not
be reissued by the Company; and, except as provided in Section 2.5 hereof in
case of the exercise of less than all of the Warrants evidenced by a Warrant
Certificate or in Section 1.4 in an exchange or transfer, no Warrant Certificate
shall be issued hereunder in lieu of such canceled Warrant Certificate. Any
Warrant Certificate so canceled shall be destroyed by the Company.

                                       2
<PAGE>

                                  ARTICLE II
                WARRANT EXERCISE PRICE AND EXERCISE OF WARRANTS

     Section 2.1  Exercise Price. Each Warrant Certificate shall, when signed by
                  --------------
the Chairman or President or any Vice President and attested to by the Secretary
or Assistant Secretary of the Company, entitle the Holder thereof to purchase
from the Company, subject to the terms and conditions of this Agreement, the
number of fully paid and nonassessable Warrant Shares evidenced thereby at a
purchase price of $8.77 per share (the "Initial Exercise Price") or such
adjusted number of Warrant Shares at such adjusted purchase price as may be
established from time to time pursuant to the provisions of Article III hereof,
payable in full in accordance with Section 2.3 hereof, at the time of exercise
of the Warrant. Except as the context otherwise requires, the term "Exercise
Price" as used in this Agreement shall mean the purchase price of one share of
Common Stock, reflecting all appropriate adjustments made in accordance with the
provisions of Article III hereof.

     Section 2.2  Registration of Warrants and Warrant Shares. The Company shall
                  -------------------------------------------
secure the effective registration of the Warrant Shares for resale under the
Securities Act of 1933, as amended (the "Securities Act") upon the terms and
subject to the conditions set forth in Appendix II to the Securities Purchase
Agreement. Promptly after a registration statement under the Securities Act
covering the Warrant Shares has become effective, the Company shall cause notice
thereof together with a copy of the prospectus covering the Warrant Shares to be
mailed to each registered Holder.

     Section 2.3  Procedure for Exercise of Warrants. The Warrants may be
                  ----------------------------------
exercised prior to the Expiration Date (as hereinafter defined) at the Exercise
Price at any time after the date hereof. The Warrants shall expire at 5:00 p.m.,
Boston time, on March 8, 2005 (the "Expiration Date"). The Warrants may be
exercised by surrendering the Warrant Certificates representing such Warrants to
the Company at its address set forth in Section 4.5 hereof, together with the
Election to Purchase duly completed and executed, accompanied by payment in
full, as set forth below, to the Company of the Exercise Price for each Warrant
Share in respect of which such Warrants are being exercised. Such Exercise Price
shall be paid in full by (i) cash or a certified check or a wire transfer in
same day funds in an amount equal to the Exercise Price multiplied by the number
of Warrant Shares then being purchased or (ii) delivery to the Company of that
number of shares of Common Stock having a Fair Market Value (as hereinafter
defined) equal to the Exercise Price multiplied by the number of Warrant Shares
then being purchased. In the alternative, the Holder of a Warrant Certificate
may exercise its right to purchase some or all of the Warrant Shares subject to
such Warrant Certificate, on a net basis, such that, without the exchange of any
funds, such Holder receives that number of Warrant Shares subscribed to pursuant
to such Warrant Certificate less that number of shares of Common Stock having an
aggregate Fair Market Value at the time of exercise equal to the aggregate
Exercise Price that would otherwise have been paid by such Holder for the number
of Warrant Shares subscribed to pursuant to such Warrant Certificate
(hereinafter, a "Net Cashless Exercise"). In any event, the Warrants shall
automatically convert into the Warrant Shares on the Expiration Date pursuant to
a Net Cashless Exercise if on the Expiration Date the Fair Market Value of the
Warrant Shares is greater than the Exercise Price, notwithstanding that the
Holder may not have provided to the Company its Election to Purchase by the
Expiration Date.

     As used herein: (a) the term "Fair Market Value," on a per share basis,
means the average of the daily Closing Prices (as hereinafter defined) of the
Common Stock for the five (5) consecutive

                                       3
<PAGE>

Trading Days (as hereinafter defined) ending the Trading Day immediately
preceding the Date of Exercise; (b) the term "Date of Exercise" with respect to
any Warrant means the date on which such Warrant is exercised as provided
herein; (c) the term "Closing Price" for any date shall mean the last sale price
reported in The Wall Street Journal regular way or, in case no such reported
            -----------------------
sale takes place on such date, the average of the last reported bid and asked
prices regular way, in either case on the principal national securities exchange
on which the Common Stock is admitted to trading or listed if that is the
principal market for the Common Stock or, if not listed or admitted to trading
on any national securities exchange or if such national securities exchange is
not the principal market for the Common Stock, the last sale price as reported
on The Nasdaq Stock Market, Inc.'s National Market ("Nasdaq") or its successor,
if any, or if the Common Stock is not so reported, the average of the reported
bid and asked prices in the over-the-counter market, as furnished by the
National Quotation Bureau, Inc., or if such firm is not then engaged in the
business of reporting such prices, as furnished by any similar firm then engaged
in such business and selected by the Company or, if there is no such firm, as
furnished by any member of the National Association of Securities Dealers, Inc.
("NASD") selected by the Company or, if the Common Stock is not quoted in the
over-the-counter market, the fair value thereof determined in good faith by the
Company's Board of Directors as of a date which is within 15 days of the date as
of which the determination is to be made; and (d) the term "Trading Days" with
respect to the Common Stock means (i) if the Common Stock is quoted on Nasdaq or
any similar system of automated dissemination of quotations of securities
prices, days on which trades may be made on such system or (ii) if the Common
Stock is listed or admitted for trading on any national securities exchange,
days on which such national securities exchange is open for business.

     Section 2.4  Issuance of Common Stock. As soon as practicable after the
                  ------------------------
Date of Exercise of any Warrants, the Company shall issue, or cause its transfer
agent to issue, a certificate or certificates for the number of full Warrant
Shares, registered in accordance with the instructions set forth in the Election
to Purchase, together with cash for fractional shares as provided in Section
3.10. All Warrant Shares issued upon the exercise of any Warrants shall be
validly authorized and issued, fully paid, non-assessable, free of preemptive
rights and (subject to Section 4.1 hereof) free from all taxes, liens, charges
and security interests in respect of the issuance thereof. Each person in whose
name any such certificate for Warrant Shares is issued shall be deemed for all
purposes to have become the holder of record of the Common Stock represented
thereby on the Date of Exercise of the Warrants resulting in the issuance of
such shares, irrespective of the date of issuance or delivery of such
certificate for Warrant Shares.

     Section 2.5  Certificates for Unexercised Warrants. In the event that,
                  -------------------------------------
prior to the Expiration Date, a Warrant Certificate is exercised in respect of
fewer than all of the Warrant Shares issuable on such exercise, a new Warrant
Certificate representing the remaining Warrant Shares shall be issued and
delivered pursuant to the provisions hereof; provided that the Company shall not
                                             --------
be required to issue any Warrant Certificate representing any fractional Warrant
Shares.

     Section 2.6  Reservation of Shares. The Company shall at all times reserve
                  ---------------------
and keep available, free from preemptive rights, for issuance upon the exercise
of Warrants, the maximum number of its authorized but unissued shares of Common
Stock which may then be issuable upon the exercise in full of all outstanding
Warrants. The Company shall from time to time take all action which may be
necessary or appropriate so that the Warrant Shares, immediately upon their
issuance

                                       4
<PAGE>

following an exercise of Warrants, will be listed or quoted, as the case may be,
on the principal securities exchanges or markets within the United States of
America, if any, on which other shares of the Common Stock are then listed.
Without limitation of Section 2.2 hereof, nothing in this Section 2.6 shall
require the Company to maintain a current registration statement or prospectus
for the Warrant Shares.

     Section 2.7  No Impairment. The Company shall not by any action, including,
                  -------------
without limitation, amending its certificate of incorporation or through any
reorganization, transfer of assets, consolidation, merger, dissolution, issue or
sale of securities or any other voluntary action, avoid or seek to avoid the
observance or performance of any of the terms of the Warrants, but will at all
times in good faith assist in the carrying out of all such terms and in the
taking of all such actions as may be necessary or appropriate to protect the
rights of the Holders against impairment. Without limiting the generality of the
foregoing, the Company will (a) not increase the par value of any Warrant Shares
receivable upon the exercise of the Warrants above the amount payable therefor
upon such exercise immediately prior to such increase in par value, (b) take all
such action as may be necessary or appropriate in order that the Company may
validly and legally issue fully paid and non-assessable Warrant Shares upon the
exercise of any Warrant, and (c) use its best efforts to obtain all such
authorizations, exemptions or consents from any public regulatory body having
jurisdiction thereof as may be necessary to enable the Company to perform its
obligations under the Warrants. Notwithstanding the foregoing paragraph, the
Company shall not be required to issue Warrant Shares upon the exercise of any
Warrant if such issuance would result in a violation by the Company of any
applicable law.

                                  ARTICLE III
                       ADJUSTMENTS AND NOTICE PROVISIONS

     Section 3.1  Adjustment of Exercise Price. Subject to the provisions of
                  ----------------------------
this Article III, the Exercise Price in effect from time to time shall, subject
to Section 3.3 hereof, be subject to adjustment in the following manner. In case
the Company shall (i) declare a dividend or make a distribution on the
outstanding shares of its Common Stock in shares of its Common Stock, (ii)
subdivide or reclassify the outstanding shares of its Common Stock into a
greater number of shares, or (iii) combine or reclassify the outstanding shares
of its Common Stock into a smaller number of shares, the Exercise Price in
effect immediately after the record date for such dividend or distribution or
the effective date of such subdivision, combination or reclassification shall be
adjusted so that it shall equal the price determined by multiplying the Exercise
Price in effect immediately prior thereto by a fraction, of which the numerator
shall be the number of shares of Common Stock outstanding immediately before
such dividend, distribution, subdivision, combination or reclassification, and
of which the denominator shall be the number of shares of Common Stock
outstanding immediately after such dividend, distribution, subdivision,
combination or reclassification. Such adjustment shall be made successively
whenever any event specified above shall occur.

     Section 3.2  Sales of Certain Securities.
                  ---------------------------

          (a)     In case the Company shall on or after the date hereof issue
or sell any shares of Common Stock or any rights, options, warrants or
convertible or exchangeable securities containing the right to subscribe for or
purchase shares of Common Stock (excluding Excluded

                                       5
<PAGE>

Securities, as defined in Subsection 3.2(b) below) at a price per share less
than seventy-five percent (75%) of the Current Market Price (as defined in
Subsection 3.2(f) below) (such amount being the "Threshold Value"), then the
Exercise Price shall be adjusted immediately thereafter so that it shall equal
the price determined by multiplying the Exercise Price in effect immediately
prior to such issuance or sale by a fraction, of which the numerator shall be
the number of shares of Fully Diluted Common Stock outstanding immediately prior
to such issuance or sale plus the number of additional shares of Common Stock
the Aggregate Consideration Receivable (as defined in Subsection 3.2(d) below)
would purchase at the Threshold Value per share on the date of such issuance or
sale, and of which the denominator shall be the number of shares of Fully
Diluted Common Stock outstanding immediately prior to such issuance or sale plus
the number of additional shares of Common Stock offered for subscription or
purchase. Such adjustment shall be made successively whenever such issuance or
sale shall occur. To the extent that any such rights, options, warrants or
convertible or exchangeable securities expire unexercised, the Exercise Price
then in effect shall be readjusted to the Exercise Price which would then be in
effect if such unexercised rights, options, warrants or convertible or
exchangeable securities had not been issued or sold.

          (b)     For the purposes of this Section 3.2,

                  (i)  "Fully Diluted Common Stock" shall mean the number of
     shares of outstanding Common Stock plus any shares of Common Stock issuable
     upon conversion of the Company's Series A Preferred Stock or any other
     outstanding debt or equity securities convertible into or exercisable for
     Common Stock or into securities convertible or exchangeable for Common
     Stock, including without limitation all options and warrants then
     outstanding.

                  (ii) "Excluded Securities" means the following:

                       (A) rights, options, warrants, or convertible or
          exchangeable securities issued in any of the transactions described in
          Section 3.5 hereof;

                       (B) shares of Common Stock issuable upon exercise of the
          Warrants or any other warrants outstanding as of the date hereof;

                       (C) shares of Common Stock issued or that may become
          issuable upon exercise of rights, options or warrants or conversion or
          exchange of convertible or exchangeable securities issued or sold
          under circumstances causing an adjustment that has already been made
          pursuant to this Section 3.2 or which would cause an adjustment but
          for Section 3.3 hereof;

                       (D) shares of Common Stock issuable upon conversion, in
          accordance with their terms, of any shares of Series A Preferred Stock
          outstanding as of the date hereof or issuable in the future upon
          conversion, in accordance with their terms, of any debt securities
          outstanding as of the date hereof;

                       (E) shares of Common Stock issued upon exercise of
          options granted under the Company's current stock option plans or
          other stock option plans adopted

                                       6
<PAGE>

          in the future by a majority of the Board of Directors of the Company,
          so long as such majority includes a majority of the outside directors
          of the Company (a "Majority Board Approval");

                       (F) shares of Common Stock issued pursuant to the
          Company's Employee Stock Purchase Plan or any comparable plan adopted
          by Majority Board Approval in the future; and

                       (G) shares of Common Stock issued in an acquisition of
          the business, stock or assets of another entity in a strategic
          transaction, or in a transaction involving a strategic partner of the
          Company, including with respect to the joint development or use of
          technology or distribution of product, which acquisition or
          transaction received Majority Board Approval.

          (c) The price per share of Common Stock referred to in Subsection
3.2(a) above shall be determined by dividing (i) the Aggregate Consideration
Receivable in respect of such rights, options, warrants or convertible or
exchangeable securities, by (ii) the total number of shares of Common Stock
covered by such rights, options, warrants or convertible or exchangeable
securities.

          (d) "Aggregate Consideration Receivable" means the aggregate amount
paid to the Company for such rights, options, warrants or convertible or
exchangeable securities, plus the aggregate consideration or premiums stated in
such rights, options, warrants or convertible or exchangeable securities to be
payable for the shares of Common Stock covered thereby.

          (e) In case the Company shall sell and issue rights, options, warrants
or convertible or exchangeable securities containing the right to subscribe for
or purchase shares of Common Stock, for a consideration consisting, in whole or
in part, of property other than cash or its equivalent, then in determining the
"price per share of Common Stock" referred to in Subsections 3.2(a) and (c)
above and the "Aggregate Consideration Receivable" referred to in Subsections
3.2(a), (c) and (d) above, the Board of Directors of the Company shall
determine, in good faith and on a reasonable basis, the fair value of said
property.

          (f) For the purpose of any computation under Subsection 3.2(a) hereof,
the "Current Market Price" per share at any date (the "Computation Date") shall
be deemed to be the average of the daily Closing Prices of the Common Stock for
the twenty (20) consecutive Trading Days ending the Trading Day immediately
preceding the Computation Date; provided, however, that if there shall have
occurred prior to the Computation Date any event described in Subsection 3.2(a)
which shall have become effective with respect to market transactions at any
time (the "Market-Effect Date") on or within such 20-day period, the Closing
Price for each Trading Day preceding the Market-Effect Date shall be adjusted,
for purposes of calculating such average, by multiplying such Closing Price by a
fraction, of which the numerator shall be the Exercise Price as in effect
immediately prior to the Computation Date and the denominator of which shall be
the Exercise Price as in effect immediately prior to the Market-Effect Date, it
being understood that the purpose of this proviso is to ensure that the effect
of such event on the market price of the Common Stock shall, as nearly as
possible, be eliminated in order that the distortion in the calculation of the
Current Market Price may be minimized. If, at the Computation Date, the Common
Stock has not

                                       7
<PAGE>

then been quoted on Nasdaq or listed or admitted for trading on any national
securities exchange for a period of twenty (20) Trading Days, the Current Market
Value shall be determined by the Board of Directors in good faith, on a
reasonable basis, as the case may be (which amount shall be subject to
adjustment in the event of a stock dividend, stock split or subdivision,
combination or reclassification of the Common Stock).

     Section 3.3  No Adjustments to Exercise Price. No adjustment in the
                  --------------------------------
Exercise Price in accordance with the provisions of Section 3.1 or Subsection
3.2(a) hereof need be made unless such adjustment would amount to a change of at
least 0.5% in such Exercise Price, provided, however, that the amount by which
                                   --------  -------
any adjustment is not made by reason of the provisions of this Section 3.3 shall
be carried forward and taken into account at the time of any subsequent
adjustment in the Exercise Price. The Exercise Price shall not be adjusted below
the par value per share of the Common Stock for the purpose of making any
adjustment as may be required pursuant to this Article III.

     Section 3.4  Adjustment of Number of Shares. Upon each adjustment of the
                  ------------------------------
Exercise Price pursuant to Section 3.1 or Subsection 3.2(a) hereof, each Warrant
shall thereupon evidence the right to purchase that number of Warrant Shares
(calculated to the nearest hundredth of a share) obtained by multiplying the
number of Warrant Shares purchasable immediately prior to such adjustment upon
exercise of the Warrant by the Exercise Price in effect immediately prior to
such adjustment and dividing the product so obtained by the Exercise Price in
effect immediately after such adjustment. In the event that the Exercise Price
may not be adjusted due to the provisions of Section 3.3 hereof, the number of
Warrant Shares purchasable upon the exercise of the Warrants shall be adjusted
hereunder as if the Exercise Price had been so adjusted.

     Section 3.5  Reorganizations. In case of any capital reorganization, other
                  ---------------
than in the cases referred to in Section 3.1 hereof, or the consolidation or
merger of the Company with or into another corporation (other than a merger or
consolidation in which the Company is the continuing corporation and which does
not result in any reclassification of the outstanding shares of Common Stock or
the conversion of such outstanding shares of Common Stock into shares of other
stock or other securities or property), or the sale or conveyance of the
property of the Company as an entirety or substantially as an entirety
(collectively such actions being hereinafter referred to as "Reorganizations"),
there shall thereafter be deliverable upon exercise of any Warrant (in lieu of
the number of Warrant Shares theretofore deliverable) the number of shares of
stock or other securities or property to which a holder of the number of Warrant
Shares which would otherwise have been deliverable upon the exercise of such
Warrant would have been entitled upon such Reorganization if such Warrant had
been exercised in full immediately prior to such Reorganization. In case of any
Reorganization, appropriate adjustment, as determined in good faith by the Board
of Directors of the Company, shall be made in the application of the provisions
herein set forth with respect to the rights and interests of Holders so that the
provisions set forth herein shall thereafter be applicable, as nearly as
possible, in relation to any shares or other property thereafter deliverable
upon exercise of Warrants. Any such adjustment shall be made by and set forth in
a supplemental agreement prepared by the Company or any successor thereto,
between the Company and any successor thereto, and shall for all purposes hereof
conclusively be deemed to be an appropriate adjustment. The Company shall not
effect any such Reorganization, unless upon or prior to the consummation thereof
the successor corporation, or if the Company shall be the surviving corporation
in any such Reorganization and

                                       8
<PAGE>

is not the issuer of the shares of stock or other securities or property to be
delivered to holders of shares of the Common Stock outstanding at the effective
time thereof, then such issuer shall assume by written instrument the obligation
to deliver to the Holder of any Warrant Certificate such shares of stock,
securities, cash or other property as such holder shall be entitled to purchase
in accordance with the foregoing provisions.

     Section 3.6  Verification of Computations. The Company shall select a firm
                  ----------------------------
of independent public accountants (which may be its outside auditors), which
selection may be changed from time to time, to verify each computation and/or
adjustment made in accordance with this Article III. The certificate, report or
other written statement of any such firm shall be conclusive evidence of the
correctness of any computation made under this Article III. Promptly upon its
receipt of such certificate, report or statement from such firm of independent
public accountants, the Company shall deliver a copy thereof to each Holder.

     Section 3.7  Notice of Certain Actions. In the event the Company shall (a)
                  -------------------------
declare any dividend payable in stock to the holders of its Common Stock or make
any other distribution in property other than cash to the holders of its Common
Stock, (b) offer to the holders of its Common Stock rights to subscribe for or
purchase any shares of any class of stock or any other rights or options, or (c)
effect any reclassification of its Common Stock (other than a reclassification
involving merely the subdivision or combination of outstanding shares of Common
Stock) or any capital reorganization or any consolidation or merger (other than
a merger in which no distribution of securities or other property is made to
holders of Common Stock) or any sale, transfer or other disposition of its
property, assets and business substantially as an entirety, or the liquidation,
dissolution or winding up of the Company; then, in each such case, the Company
shall cause notice of such proposed action to be mailed to each Holder at least
thirty (30) days prior to such action; provided, however, that in the event that
                                       --------  -------
the Company provides public notice of such action specifying the information set
forth below at least fifteen (15) days prior to such action, the Company shall
be deemed to have satisfied its obligation to provide notice pursuant to this
Section 3.7. Such notice shall specify the date on which the books of the
Company shall close, or a record be taken, for determining holders of Common
Stock entitled to receive such stock dividend or other distribution or such
rights or options, or the date on which such reclassification, reorganization,
consolidation, merger, sale, transfer, other disposition, liquidation,
dissolution, winding up or exchange shall take place or commence, as the case
may be, and the date as of which it is expected that holders of record of Common
Stock shall be entitled to receive securities or other property deliverable upon
such action, if any such date has been fixed. Such notice shall be mailed in the
case of any action covered by paragraph (a) or (b) of this Section 3.7, at least
ten (10) days prior to the record date for determining holders of the Common
Stock for purposes of receiving such payment or offer, and in the case of any
action covered by this paragraph (c), at least ten (10) days prior to the
earlier of the date upon which such action is to take place or any record date
to determine holders of Common Stock entitled to receive such securities or
other property.

     Section 3.8  Certificate of Adjustments. Whenever any adjustment is to be
                  --------------------------
made pursuant to this Article III, the Company shall prepare a certificate
executed by the Chief Financial Officer of the Company, setting forth such
adjustments to be mailed to each Holder at least fifteen (15) days prior
thereto, such notice to include in reasonable detail (a) the events
precipitating the adjustment, (b) the computation of any adjustments, and (c)
the Exercise Price and the number of shares or the

                                       9
<PAGE>

securities or other property purchasable upon exercise of each Warrant after
giving effect to such adjustment. Such Certificate shall be accompanied by the
accountant's verification required by Section 3.6 hereof.

     Section 3.9  Warrant Certificate Amendments. Irrespective of any
                  ------------------------------
adjustments pursuant to this Article III, Warrant Certificates theretofore or
thereafter issued need not be amended or replaced, but certificates thereafter
issued shall bear an appropriate legend or other notice of any adjustments;
provided the Company may, at its option, issue new Warrant Certificates
--------
evidencing Warrants in such form as may be approved by its Board of Directors to
reflect any adjustment in the Exercise Price and number of Warrant Shares
purchasable under the Warrants.

     Section 3.10  Fractional Shares. The Company shall not be required upon the
                   -----------------
exercise of any Warrant to issue fractional Warrant Shares which may result from
adjustments in accordance with this Article III to the Exercise Price or number
of Warrant Shares purchasable under each Warrant. If more than one Warrant is
exercised at one time by the same Holder, the number of full Warrant Shares
which shall be issuable upon the exercise thereof shall be computed based on the
aggregate number of Warrant Shares purchasable upon exercise of such Warrants.
With respect to any final fraction of a share called for upon the exercise of
any Warrant or Warrants, the Company shall pay an amount in cash to the Holder
of the Warrants in respect of such final fraction in an amount equal to the Fair
Market Value of a share of Common Stock as of the Date of Exercise of such
Warrants, multiplied by such fraction. All calculations under this Section 3.10
shall be made to the nearest hundredth of a share.

                                  ARTICLE IV
                                 MISCELLANEOUS

     Section 4.1  Payment of Taxes and Charges. The Company will pay all taxes
                  ----------------------------
(other than income taxes) and other government charges in connection with the
issuance or delivery of the Warrants and the initial issuance or delivery of
Warrant Shares upon the exercise of any Warrants and payment of the Exercise
Price. The Company shall not, however, be required to pay any additional
transfer taxes in connection with the subsequent transfer of Warrants or any
transfer involved in the issuance and delivery of Warrant Shares in a name other
than the name in which the Warrants to which such issuance relates were
registered, and, if any such tax would otherwise be payable by the Company, no
such issuance or delivery shall be made unless and until the person requesting
such issuance has paid to the Company the amount of any such tax, or it is
established to the reasonable satisfaction of the Company that any such tax has
been paid.

     Section 4.2  Changes to Agreement. The Company, when authorized by its
                  --------------------
Board of Directors, with the written consent of Holders of at least a majority
of the outstanding Warrants may amend or supplement this Agreement. The Company
may, without the consent or concurrence of any Holder, by supplemental agreement
or otherwise, make any changes or corrections in this Agreement that the Company
shall have been advised by counsel (a) are required to cure any ambiguity or to
correct any defective or inconsistent provision or clerical omission or mistake
or manifest error herein contained, (b) add to the covenants and agreements of
the Company in this Agreement such further covenants and agreements thereafter
to be observed, or (c) result in the surrender of any right or power reserved to
or conferred upon the Company in this Agreement, in

                                      10
<PAGE>

each case which changes or corrections do not and will not adversely affect,
alter or change the rights, privileges or immunities of the Holders.

     Section 4.3  Assignment. All the covenants and provisions of this Agreement
                  ----------
by or for the benefit of the Company or the Holders shall bind and inure to the
benefit of their respective successors and assigns.

     Section 4.4  Successor to Company. In the event that the Company merges or
                  --------------------
consolidates with or into any other corporation or sell or otherwise transfers
its property, assets and business substantially as an entirety to a successor
corporation, the Company shall use reasonable commercial efforts to have such
successor corporation assume each and every covenant and condition of this
Agreement to be performed and observed by the Company.

     Section 4.5  Notices. Any notice or demand required by this Agreement to be
                  -------
given or made by any Holder to or on the Company shall be sufficiently given or
made if sent by first-class or registered mail, postage prepaid, addressed as
follows:

                  Careside, Inc.
                  6100 Bristol Parkway
                  Culver City, CA 90230
                  Attn: W. Vickery Stoughton

          With a copy to:

                  Pepper Hamilton LLP
                  3000 Two Logan Square
                  Eighteenth and Arch Streets
                  Philadelphia, PA 19103
                  Attn: Julia D. Corelli, Esq.

Any notice or demand required by this Agreement to be given or made by the
Company to or on any Holder shall be sufficiently given or made if sent by
first-class or registered mail, postage prepaid, addressed to such Holder and
sent to the following address:

                  H.C. Wainwright & Co., Inc.
                  One Boston Place, 40th Floor
                  Boston, MA 02108
                  Attn: Edward P. Crouch

          With a copy to:

                  Goodwin, Procter & Hoar  LLP
                  Exchange Place
                  Boston, MA 02109-2881
                  Attn: David F. Dietz, P.C.

                                      11
<PAGE>

Any notice or demand required by this Agreement to be given or made by the
Company to or on any Holder shall be sufficiently given or made, whether or not
such holder receives the notice, five (5) days after mailing, if sent by first-
class or registered mail, postage prepaid, addressed to such Holder at its last
address as shown on the books of the Company. Otherwise, such notice or demand
shall be deemed given when received by the party entitled thereto.

     Section 4.6   Defects in Notice. Failure to file any certificate or notice
                   -----------------
or to mail any notice, or any defect in any certificate or notice pursuant to
this Agreement shall not affect in any way the rights of any Holder or the
legality or validity of any adjustment made pursuant to Section 3.1 or Section
3.2 hereof, or any transaction giving rise to any such adjustment, or the
legality or validity of any action taken or to be taken by the Company.

     Section 4.7   Governing Law. This Agreement and each Warrant Certificate
                   -------------
issued hereunder shall be governed by the laws of the Commonwealth of
Massachusetts without regard to principles of conflicts of laws thereof.

     Section 4.8   Standing. Nothing in this Agreement expressed and nothing
                   --------
that may be implied from any of the provisions hereof is intended, or shall be
construed, to confer upon, or give to, any person or corporation other than the
Company and the Holders of any right, remedy or claim under or by reason of this
Agreement or of any covenant, condition, stipulation, promise or agreement
contained herein; and all covenants, conditions, stipulations, promises and
agreements contained in this Agreement shall be for the sole and exclusive
benefit of the Company and its successors, and the Holders.

     Section 4.9   Headings. The descriptive headings of the articles and
                   --------
sections of this Agreement are inserted for convenience only and shall not
control or affect the meaning or construction of any of the provisions hereof.

     Section 4.10  Counterparts. This Agreement may be executed in any number of
                   ------------
counterparts, each of which so executed shall be deemed to be an original, and
all of which together shall constitute one and the same instrument.

     Section 4.11  Availability of the Agreement. The Company shall keep copies
                   -----------------------------
of this Agreement available for inspection by Holders during normal business
hours. Copies of this Agreement may be obtained upon written request addressed
to the Company at the address set forth in Section 4.5 hereof.

     Section 4.12  Entire Agreement. This Agreement, including the Exhibits
                   ----------------
referred to herein and the other writings specifically identified herein or
contemplated hereby, is complete, reflects the entire agreement of the parties
with respect to its subject matter, and supersedes all previous written or oral
negotiations, commitments and writings.

                                      12
<PAGE>

                               WARRANT AGREEMENT
                            COMPANY SIGNATURE PAGE

     IN WITNESS WHEREOF, this Warrant Agreement has been duly executed by the
parties as of the day and year first above written.

                                             CARESIDE, INC.,
                                             a Delaware corporation


                                             By:___________________________
                                             Name:
                                             Title:
<PAGE>

                               WARRANT AGREEMENT
                           PURCHASER SIGNATURE PAGE

Accepted and Agreed as of the date first written above.


                                             H.C. Wainwright & Co., Inc.


                                             By:___________________________
                                             Name:
                                             Title:
<PAGE>

                    EXHIBIT A - FORM OF WARRANT CERTIFICATE

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, NOR PURSUANT TO THE SECURITIES OR "BLUE
SKY" LAWS OF ANY STATE. SUCH SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED,
PLEDGED, HYPOTHECATED OR OTHERWISE ASSIGNED, EXCEPT PURSUANT TO (i) A
REGISTRATION STATEMENT WITH RESPECT TO SUCH SECURITIES WHICH IS EFFECTIVE UNDER
SUCH ACT, (ii) RULE 144 OR RULE 144A UNDER SUCH ACT, OR (iii) ANY OTHER
EXEMPTION FROM REGISTRATION UNDER SUCH ACT RELATING TO THE DISPOSITION OF
SECURITIES. ANY TRANSFER OF THE SECURITIES REPRESENTED BY THIS CERTIFICATE IS
SUBJECT TO THE TERMS AND CONDITIONS CONTAINED IN A SECURITIES PURCHASE AGREEMENT
DATED AS OF MARCH 8, 2000, AS AMENDED FROM TIME TO TIME, A COMPLETE AND CORRECT
COPY OF THE FORM OF WHICH WILL BE FURNISHED BY THE ISSUER TO THE HOLDER HEREOF
UPON WRITTEN REQUEST AND WITHOUT CHARGE. SUCH AGREEMENT, AMONG OTHER THINGS,
RESTRICTS THE DETACHMENT OF THE COMMON STOCK PURCHASE WARRANTS FROM THE SENIOR
DISCOUNT NOTE ATTACHED HERETO.

No. HCW W-1

                       Certificate for [      ] Warrants

                       NOT EXERCISABLE AFTER 5:00 P.M.,
                         BOSTON TIME, ON MARCH 8, 2005

                                CARESIDE, INC.

                   COMMON STOCK PURCHASE WARRANT CERTIFICATE

     THIS CERTIFIES that H.C. Wainwright & Co., Inc. or its registered assigns
is the registered holder (the "Registered Holder") of Warrants set forth above,
each of which represents the right to purchase one fully paid and non-assessable
share of common stock, par value $.01 per share (the "Common Stock"), of
Careside, Inc., a Delaware corporation (the "Company"), at the Exercise Price
(as defined in the Warrant Agreement) at the times specified in the Warrant
Agreement, by surrendering this Warrant Certificate, with the form of Election
to Purchase attached hereto duly executed and by paying in full the Exercise
Price. Payment of the Exercise Price shall be made as set forth in the Warrant
Agreement (as hereinafter defined). No Warrant may be exercised after 5:00 P.M.,
Boston time, on March 8, 2005 (the "Expiration Date"). All Warrants evidenced
hereby shall thereafter become void, subject to the terms of the Warrant
Agreement hereinafter referred to.

     Prior to the Expiration Date, subject to any applicable laws, rules or
regulations restricting transferability and to any restriction on
transferability that may appear on this Warrant Certificate and in accordance
with the terms of the Warrant Agreement hereinafter referred to, the Registered
Holder shall be entitled to transfer this Warrant Certificate, in whole or in
part, upon surrender of this Warrant Certificate at the principal office of the
Company with the form of assignment set forth hereon duly executed. Upon any
such transfer, a new Warrant Certificate or Warrant Certificates

                                      A-1
<PAGE>

representing the same aggregate number of Warrants to purchase the shares of the
Common Stock will be issued in accordance with instructions in the form of
assignment.

     Upon the exercise of less than all of the Warrants to purchase the shares
of the Common Stock evidenced by this Warrant Certificate, there shall be issued
to the Registered Holder a new Warrant Certificate in respect of the Warrants
not exercised.

     Prior to the Expiration Date, the Registered Holder shall be entitled to
exchange this Warrant Certificate, with or without other Warrant Certificates,
for another Warrant Certificate or Warrant Certificates for the same aggregate
number of Warrants to purchase the shares of the Common Stock, upon surrender of
this Warrant Certificate at the principal office of the Company.

     Upon certain events provided for in the Warrant Agreement, the Exercise
Price and the number of shares of Common Stock issuable upon the exercise of
each Warrant are required to be adjusted.

     No fractional shares will be issued upon the exercise of Warrants. As to
any final fraction of a share of Common Stock which the Registered Holder of one
or more Warrant Certificates, the rights under which are exercised in the same
transaction, would otherwise be entitled to purchase upon such exercise, the
Company shall pay the cash value thereof determined as provided in the Warrant
Agreement. No Warrant Certificate representing any fractional Warrant Shares
will be issued.

     This Warrant Certificate is issued under and in accordance with the Warrant
Agreement dated as of March 8, 2000 (the "Warrant Agreement") by and among the
Company and the Purchaser (as defined in the Warrant Agreement) and is subject
to the term and provisions contained in the Warrant Agreement. All capitalized
terms not defined herein shall have the meanings given such terms as set forth
in the Warrant Agreement.

This Warrant Certificate shall not entitle the Registered Holder to any of the
rights of a stockholder of the Company, including, without limitation, the right
to vote, to receive dividends and other distributions, or to attend or receive
any notice of meetings of stockholders or any other proceedings of the Company.

                                      A-2
<PAGE>

     IN WITNESS WHEREOF, the Company has caused this Warrant Certificate to be
duly executed under its facsimile corporate seal.

                                             CARESIDE, INC.


                                             By: ____________________________
                                             Name:
                                             Title:

[Seal]                                       Attest:


                                             By:_____________________________
                                             Name:
                                             Title: Secretary

                                      A-3
<PAGE>

                             [Form of Assignment]


     FOR VALUE RECEIVED, the undersigned hereby irrevocably sells, assigns and
transfers unto the Assignee named below all of the rights of the undersigned
represented by the within Warrant Certificate, with respect to the number of
Warrants to purchase the shares of the Common Stock set forth below:

     Name of Assignee              Address                  No. of Warrants
     ----------------              -------                  ---------------




and does hereby irrevocably constitute and appoint _____________________ true
and lawful Attorney, to make such transfer on the books of Careside, Inc.,
maintained for that purpose, with full power of substitution in the premises.

Dated: ______________, _____          __________________________________________
                                      Signature


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

                                      A-4
<PAGE>

                        [Form of Election To Purchase]


     The undersigned hereby irrevocably elects to exercise ____________ of the
Warrants represented by this Warrant Certificate and to purchase the shares of
Common Stock issuable upon the exercise of said Warrants, and requests that
certificates for such shares be issued and delivered as follows:

ISSUE TO:_______________________________________________________________________
                                    (NAME)

________________________________________________________________________________
                         (ADDRESS, INCLUDING ZIP CODE)

________________________________________________________________________________
               (SOCIAL SECURITY OR OTHER IDENTIFICATION NUMBER)

DELIVER TO:_____________________________________________________________________
                                    (NAME)

at______________________________________________________________________________
                         (ADDRESS, INCLUDING ZIP CODE)

     In full payment of the purchase price with respect to the exercise of
Warrants to purchase shares of the Common Stock, the undersigned:

     [_]  hereby tenders payment of $________ by cash, certified check,
          cashier's check or money order payable in United States currency to
          the order of the Company; or

     [_]  hereby delivers to the Company that number of shares of Common Stock
          having a Fair Market Value (as defined in the Warrant Agreement) equal
          to the Exercise Price multiplied by the number of Warrant Shares being
          purchased; or

     [_]  hereby makes a Net Cashless Exercise (as defined in the Warrant
          Agreement).

     If the number of Warrants to purchase the shares of the Common Stock hereby
exercised is less than all the Warrants represented by this Warrant Certificate,
the undersigned requests that a new Warrant Certificate representing the number
of such full Warrants not exercised be issued and delivered as follows:

                                      A-5
<PAGE>

ISSUE TO:_______________________________________________________________________
                                    (NAME)

________________________________________________________________________________
                         (ADDRESS, INCLUDING ZIP CODE)

________________________________________________________________________________
                 (SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER)

DELIVER TO:_____________________________________________________________________
                                    (NAME)

at______________________________________________________________________________
                         (ADDRESS, INCLUDING ZIP CODE)


Date: ______________, ______            ________________________________________
                                        Signature

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

                                        PLEASE INSERT SOCIAL SECURITY OR TAX
                                        I.D. NUMBER OF HOLDER


                                        ________________________________________

                                      A-6