<PAGE>

3.2   CERTIFICATE OF DESIGNATION OF SERIES C PREFERRED STOCK FILED ON
      MARCH 9,1999.







<PAGE>

                                  STATE OF DELAWARE
                                                                PAGE 1
                           OFFICE OF THE SECRETARY OF STATE
                           -------------------------------

      I, EDWARD J. FREEL, SECRETARY OF STATE OF THE STATE OF DELAWARE, DO
HEREBY CERTIFY THE ATTACHED IS A TRUE AND CORRECT COPY OF THE CERTIFICATE OF
DESIGNATION OF "SERACARE, INC.", FILED IN THIS OFFICE ON THE NINTH DAY OF MARCH,
A.D. 1999, AT 9 O'CLOCK A.M.

      A FILED COPY OF THIS CERTIFICATE HAS BEEN FORWARDED TO THE KENT COUNTY
RECORDER OF DEEDS.




                                             /s/ Edward J. Freel
                                      ------------------------------------------
               [SEAL]                   EDWARD J. FREEL, SECRETARY OF STATE



                                        AUTHENTICATION:     9618663

                                                  DATE:     03-10-99

<PAGE>

                                                          STATE OF DELAWARE
                                                          SECRETARY OF STATE
                                                       DIVISION OF CORPORATIONS
                                                       FILED 09:00 AM 03/09/1999
                          CERTIFICATE OF DESIGNATIONS     991090495 - 2275058

                                          OF

                                    SERACARE, INC.

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

          Pursuant to Section 151 of the Delaware General Corporation Law
(the "GCL") SERACARE, INC., a Delaware corporation (the "Corporation"),
certifies as follows:

          FIRST: Under the authority contained in Articles FOURTH and SIXTH of
the Restated Certificate of Incorporation of the Corporation, the Board of
Directors of the Corporation has classified an aggregate of twenty five thousand
(25,000) shares of the authorized but unissued shares of Preferred Stock of the
Corporation into a series which shall be designated "Series C Convertible
Preferred Stock."

          SECOND: The following resolution was adopted by the Board of Directors
on January 27, 1999 and such resolution has not been modified and is in full
force and effect on the date hereof:

          RESOLVED, that the Board of Directors hereby creates, from the
authorized but unissued shares of Preferred Stock of the Corporation, a series
of convertible Preferred Stock designated as Series C Convertible Preferred
Stock, par value $0.001 per share (the "SERIES C PREFERRED Stock"), and hereby
fixes the powers, designations, preferences and relative, participating,
optional or other special rights, and the qualifications, limitations or
restrictions thereof, of the shares of such series, as follows:

          Section 1. SERIES C PREFERRED STOCK DIVIDENDS.

          The holders of the Series C Preferred Stock shall be entitled to
receive dividends thereon at the annual rate of ten percent (10%) of the
Liquidation Preference per share, payable quarterly in arrears, from the date
funds are received by the Corporation.

          Section 2. LIQUIDATION PREFERENCES.

          Subject to the holders' conversion rights provided below herein, upon
any liquidation (complete or partial), dissolution or winding up of the
Corporation, or any similar distribution of its assets to its stockholders which
results in a return of capital, whether voluntary or involuntary, the holders of
the Series C Preferred Stock shall be entitled, before any distribution or
payment is made upon any Junior Securities (thereinafter defined) of the
Corporation, to be paid out of the assets of the Corporation available for
distribution

<PAGE>

to its stockholders (whether from capital, surplus or earnings) an amount in
cash equal to the sum of $100 (the "LIQUIDATION PREFERENCE"), and shall not be
entitled to any further payment. The term "Junior Security" shall mean the
Corporation's Common Stock and all other equity securities of the Corporation
which are junior in rights and liquidation preference to the Series C Preferred
Stock. Written notice of such liquidation, dissolution, winding up or other
distribution of assets, stating a payment date, the amount of the payment and
the place where the amounts distributable shall be payable, shall be mailed by
certified or registered mail, return receipt requested, not less than 60 days
prior to the payment date stated therein, to each record holder of any share of
Series C Preferred Stock entitled thereto at the address for such record holder
shown on the Corporation's records. A consolidation or merger of the Corporation
into any other corporation or corporations, or a sale of all or substantially
all of the assets of the Corporation, shall, at the option of the holders of the
Series C Preferred Stock, be deemed a liquidation, dissolution or winding up
within the meaning of this Section 2 if the shares of stock of the Corporation
outstanding immediately prior to such transaction represent immediately after
such transaction less than a majority of the voting power of the surviving
corporation (or of the acquiror of the Corporation's assets in the case of a
sale of assets). Such option may be exercised by the vote or written consent of
holders of a majority of the Series C Preferred Stock at any time within thirty
calendar days after written notice (which shall be given promptly) of the
essential terms of such transaction shall have been given to the holders of the
Series C Preferred Stock in the manner provided by law for the giving of notice
of meetings of shareholders.

          Section 3. REDEMPTIONS OF SERIES C PREFERRED STOCK.

          3.1 REDEMPTION UPON CORPORATE CHANGE. (a) At any time after the
Series C Preferred Stock is convertible by the holders thereof in accordance
with Section 4.2(a), if a Corporate Change is to occur, the Corporation shall
redeem all of the outstanding Series C Preferred Stock immediately prior to the
consummation of such Corporate Change. Upon any such redemption, the Redemption
Price per share of Series C Preferred Stock shall be an amount equal to the
Liquidation Preference. Written notice of any impending Corporate Change, and
the substance and intended date of consummation thereof, shall be mailed by
certified or registered mail, return receipt requested, not more than sixty (60)
nor less than ten (10) days prior to the date of consummation thereof, to the
Purchaser at the address shown on the Corporation's record. Notwithstanding the
foregoing, in the event that a holder shall have delivered a Conversion Notice
to the Corporation prior to any Corporate Change, the Corporation's redemption
rights under this Section 3.1 shall terminate as to


                                       2
<PAGE>

any shares of Series C Preferred Stock which are the subject of such holder's
Conversion Notice.

          (b) "CORPORATE CHANGE" means (i) the sale, exchange or transfer of
all or substantially all of the Corporation's assets to an unaffiliated third
party, or (ii) any transaction or series of related transactions in which one
(1) or more persons (other than a holder of Series C Preferred Stock or an
affiliate thereof), other than the holders of a majority of the shares of Common
Stock outstanding on the date the Series C Preferred Stock is issued, shall
directly or indirectly acquire ownership of or control over capital stock (not
including shares held or controlled by them on the date of original issuance of
the Series C Preferred Stock) of the Corporation (or securities exchangeable for
or convertible into such stock) entitled to elect fifty percent (50%) or more of
the Corporation's Board of Directors and representing at least fifty percent
(50%) of the number of shares of Common Stock outstanding. Notwithstanding the
foregoing, no Corporate Change shall be deemed to have occurred as a result of
(A) the exercise of any options or warrants outstanding on the date hereof or
(B) any public offering of securities by the Corporation.

          3.2 NOTICE OF REDEMPTION. Except as otherwise expressly provided
herein, notice of any redemption of Series C Preferred Stock, specifying the
time and place of redemption, the Redemption Price and the Section and
paragraph pursuant to which such redemption is being made, shall be mailed by
certified or registered mail, return receipt requested, to each holder of
record of shares of Series C Preferred Stock to be redeemed, at the address
for such holder shown on the Corporation's records, not more than sixty (60)
nor less than thirty (30) days (or ten (10) days, in the case of a redemption
pursuant to Section 3.1) prior to the date on which such redemption is to be
made. Upon mailing any such notice of redemption the Corporation shall become
obligated to redeem at the time of redemption specified therein (the
"REDEMPTION DATE") all shares of Series C Preferred Stock therein specified.

          3.3 RIGHTS AFTER REDEMPTION DATE. Provided that the Redemption Price
is paid in full on the applicable Redemption Date, all rights of the holder of
such shares of Series C Preferred Stock as a stockholder of the Corporation, by
reason of the ownership of such shares, shall cease, except the right to receive
the Redemption Price of such shares upon presentation and surrender of the
certificate representing such shares, and such shares shall not after such
Redemption Date be deemed to be outstanding.

          3.4  DEPOSIT OF REDEMPTION PRICE. If on or before the date of
redemption specified in any notice of redemption of any

                                       3

<PAGE>

share of Series C Preferred Stock, the Corporation shall irrevocably deposit the
amount of the Redemption Price thereof with a bank or trust company having an
office in the City of New York, designated in such notice of redemption, in
trust for the benefit of the holder of such share of Series C Preferred Stock,
such share of Series C Preferred Stock shall be deemed to have been redeemed on
the date so specified, whether or not the certificate for such share shall be
surrendered for redemption and canceled.

          Section 4. CONVERSION OF SERIES C PREFERRED STOCK.

          4.1 AUTOMATIC CONVERSION BY CORPORATION. Providing: (A) the
Corporation has on file an effective registration statement on the date of such
Automatic Conversion, and; (B) the closing (Last Trade) price of the Common
Stock averages in excess of $7.00 per share for a thirty consecutive trading day
period prior to such Automatic Conversion; then, at the option of the
Corporation, the Corporation may automatically convert any or all shares of
Series C Preferred Stock then issued and outstanding into such number of fully
paid and non-assessable whole shares of Common Stock which is obtained by
multiplying the number of shares of Series C Preferred Stock so to be converted
by the Liquidation Preference of such shares plus any accrued but unpaid
interest and dividing the result by the Conversion Price (as defined in Section
4.4) then in effect.

          4.2  CONVERSION RIGHTS OF HOLDERS OF SERIES C PREFERRED STOCK AND
PROCEDURES.

          (a) The shares of Series C Preferred Stock shall be convertible by the
Holders thereof in accordance with the terms of this Section 4, at the option of
the Holder thereof at any time unless or until such Series C Preferred Stock has
been converted by the Corporation pursuant to Section 4.1 above. Series C
Preferred Stock shall be convertible into such number of fully paid and
non-assessable whole shares of Common Stock which is obtained by multiplying the
number of shares of Series C Preferred Stock so to be converted by the
Liquidation Preference of such shares and dividing the result by the Conversion
Price (as defined in Section 4.4) then in effect.

          (b) A holder of shares of Series C Preferred Stock may, at any time,
convert pursuant to this Section 4 all or any part (in whole numbers of shares
only) of the shares of Series C Preferred Stock held by such holder into fully
paid and non-assessable shares of Common Stock. Provided that such Automatic
Conversion is effected, the right to convert as to any particular share shall
terminate at the close of business on the day immediately prior to the date
fixed for automatic Conversion of the Series C Preferred Stock pursuant to
section 4.1 or upon


                                       4

<PAGE>

any liquidation, dissolution, winding up or similar distribution of the
Corporation.

          (c)  Each conversion of Series C Preferred Stock shall be effected by
the surrender of the certificate or certificates representing the shares to be
converted at "the principal office of the Corporation (or such other office or
agency of the Corporation as the Corporation may designate by notice in writing
to the holder or holders of the Series C Preferred Stock) at any time during its
usual business hours, together with written notice by the holder of such Series
C Preferred Stock (a "CONVERSION NOTICE") stating that such holder desires to
convert the shares, or a stated number of the shares, represented by such
certificate or certificates which notice shall also specify the name or names
(with addresses) and denominations in which the certificate or certificates for
Common Stock shall be issued and shall include instructions for delivery
thereof. Such conversion shall be deemed to have been effected as of the close
of business on the date on which such certificate or certificates shall have
been surrendered and such notice shall have been received, and as of such date
(the "CONVERSION DATE") the rights of the holder of such Series C Preferred
Stock (or specified portion thereof) as such holder shall cease and the person
or persons in whose name or names any certificate or certificates for shares of
Common Stock are to be issued upon such conversion shall be deemed to have
become the holder or holders of record of the shares of Common Stock represented
thereby.

          (d)  As soon as possible after the Conversion Date (and in no event
more than 30 days after the Conversion Date), the Corporation shall deliver to
the converting holder or, with respect to the certificate(s) specified in (i)
below, as specified by such converting holder:

          (i)  a certificate or certificates representing the number of shares
     of Common Stock issuable by reason of such conversion registered in such
     name or names and such denomination or denominations as the converting
     holder shall have specified; and

          (ii)  a certificate representing any shares of Series C Preferred
     Stock which shall have been represented by the certificate or certificates
     which shall have been delivered to the Corporation in connection with such
     conversion but which shall not have been converted; and

          (iii) a payment of cash in an amount equal to the value of any
     fractional share of Common Stock that otherwise would be issuable in
     connection with the Series C Preferred Stock converted.


                                       5

<PAGE>

          4.3 AUTHORIZATION AND ISSUANCE OF COMMON STOCK. The Corporation
covenants and agrees that:

          (a)  The Corporation will at all times reserve and keep available out
of its authorized but unissued shares of Common Stock, solely for the purpose of
issuing upon the conversion of the Series C Preferred Stock as provided in this
Section 4 such number of shares of Common Stock as shall then be issuable upon
the conversion of all outstanding shares of Series C Preferred Stock. The
corporation covenants that all shares of Common Stock which shall be so issuable
shall, when issued, be duly and validly issued, fully paid and non-assessable
and free from all taxes, liens, and charges. The Corporation will take all such
action as may be necessary to assure that all shares of Common Stock may be so
issued without violation of any applicable law or regulation or any requirements
of any domestic stock exchange upon which any shares of Common Stock may be
listed.

          (b) The Corporation will not take any action which results in any
adjustment of the number of shares of Common Stock which may be acquired upon
conversion of a share of Series C Preferred Stock if after such action the total
number of shares of Common Stock issuable upon conversion of the Series C
Preferred Stock then Outstanding, together with the total number of shares of
Common Stock then Outstanding and the total number of shares of Common Stock
reserved for any purpose other than issuance upon conversion of the Series C
Preferred Stock, would exceed the total number of shares of Common Stock then
authorized by the Corporation's Restated Certificate of Incorporation.

          (c) The issuance of certificates for shares of Common Stock upon
conversion of shares of the Series C Preferred Stock shall be made without
charge to the holders of such shares for any issuance tax in respect thereof, or
other cost incurred by the Corporation in connection with such conversion and
the related issuance of shares of Common Stock, provided that the Corporation
shall not be required to pay any tax which may be payable in respect of any
transfer involved in the issuance and delivery of any certificate in a name
other than that of the holder of the Series C Preferred Stock converted.

          (d) The Corporation will not close its books against the transfer of
any share of Series C Preferred Stock or of any share of Common Stock issued or
issuable upon the conversion of such shares in any manner which interferes with
the timely conversion of such shares.


                                       6

<PAGE>

          4.4  CONVERSION PRICE.

          (a) The initial conversion price shall be four dollars and fifty cents
($4.50) and may be adjusted from time to time as defined in 4.4 (b) the
"CONVERSION PRICE").

          (b)  If the Common Stock underlying the Convertible Preferred is not
registered pursuant to the 1933 Securities Act within 90 days of the Closing
Date of this agreement, the Conversion Price of the Series C Convertible
Preferred Stock shall be permanently reduced by $.50. In addition, the
Conversion Price shall be permanently reduced by an additional $.25 on each
monthly anniversary thereafter until such registration statement becomes
effective.

          Section 5. ANTI-DILUTION PROVISIONS

          5.1  SUBDIVISIONS AND COMBINATIONS. In the event that the Corporation
shall at any time subdivide (by any stock split, stock dividend or otherwise)
one or more classes of its outstanding Common Stock into a greater number of
shares of Common Stock, the Conversion Price in effect immediately prior to such
subdivision forthwith shall be proportionately reduced. Conversely, in the event
the outstanding shares of one or more classes of the Common Stock shall be
combined into a smaller number of shares (by reverse stock split or otherwise),
the Conversion Price in effect immediately prior to such combination shall be
proportionately increased.

          5.2  DIVIDENDS. In the event that the Corporation declares a dividend
(other than a cash dividend payable out of earnings or earned surplus) upon
Common Stock, then at the option of the holders of a majority of the outstanding
shares of Series C Preferred Stock,

            (1)  the Corporation shall pay over to each holder, on the dividend
     payment date, the stock or other securities and other property which holder
     would have received if such holder had converted all of his or its shares
     of Series C Preferred Stock into Common Stock and had been the record
     holder of such Common Stock on the date on which a record is taken for the
     purpose of such dividend, or, if a record is not taken, the date as of
     which the holders of Common Stock of record entitled to such dividend are
     to be determined, or

            (2) the Conversion Price in effect immediately prior to the
     declaration of such dividend shall be reduced by an amount equal to the
     fair value of such dividend per share (as reasonably determined by the
     Board of Directors of the Corporation), such reduction to be effective on
     the date


                                       7

<PAGE>

     an of which a record is taken for purposes of such dividend, or if a record
     is not taken, the date as of which holders of record of Common Stock
     entitled to such dividend are determined, or

            (3) in the case of a dividend consisting of stock or securities
     (other than Common Stock, Options or Convertible Securities) or other
     property distributable to holders of Common Stock, the holder of Series C
     Preferred Stock may elect that, in lieu of (1) or (2) above, lawful and
     adequate provisions shall be made (including without limitation any
     necessary reduction in the Conversion Price) whereby such holder of Series
     C Preferred Stock shall thereafter have the right to purchase and/or
     receive, on the terms and conditions specified in this Certificate of
     Designations and in addition to the shares of Common Stock receivable
     immediately prior to the declaration of such dividend upon conversion of
     his or its shares of Series C Preferred Stock, such shares of stock,
     securities or property as are distributable with respect to outstanding
     shares of Common Stock equal to the number of shares of Common Stock
     receivable immediately prior to such declaration upon conversion of his or
     its shares of Series C Preferred Stock, to the end that the provisions
     hereof (including without limitation provisions for adjustments of the
     Conversion Price and of the number of shares receivable upon such
     conversion) shall thereafter be applicable, as nearly as may be, in
     relation to such shares of stock, securities or property.

          For the purposes of this Section 5.2, "DIVIDEND" shall mean any
distribution to the holders of Common Stock as such, and a dividend shall be
considered payable out of earnings or earned surplus (other than revaluation or
paid-in surplus) only to the extent that such earnings or earned surplus are
charged an amount equal to the fair value of such dividend as reasonably
determined by the Board of Directors of the Corporation.

          5.3  REORGANIZATION RECLASSIFICATION, Consolidation, MERGER OR SALE.
If any capital reorganization or reclassification of the capital stock of the
Corporation, or any consolidation or merger of the Corporation with or into
another corporation, or any sale of all or substantially all of the
Corporation's assets to another corporation shall be effected in such a way that
holders of Common Stock shall be entitled to receive (either directly or upon
subsequent liquidation) stock, securities or assets with respect to or in
exchange for Common Stock, then, as a condition of such reorganization,
reclassification, consolidation, merger or sale, lawful and adequate provision
(as determined reasonably and in good faith by the Board of Directors of the
Corporation) shall be made whereby each of the holders of the Series C Preferred
Stock


                                       8

<PAGE>

shall thereafter have the right to acquire and receive upon the basis and upon
the terms and conditions specified herein and in lieu of the shares of Common
Stock of the Corporation immediately theretofore acquirable and receivable upon
the conversion of such holder's shares, such shares of stock, securities or
assets as may be issued or payable with respect to or in exchange for a number
of outstanding shares of Common Stock equal to the number of shares of Common
Stock immediately theretofore acquirable and receivable upon conversion of such
shares had such reorganization, reclassification, consolidation, merger or sale
not taken place, and in any such case appropriate provision shall be made with
respect to such holder's rights and interests to the end that the provisions of
this Section 5 (including without limitation provisions for adjustments of the
Conversion Price and of the number of shares of Common Stock acquirable and
receivable upon the exercise of the conversion rights granted in this Section 5)
shall thereafter be applicable in relation to any shares of stock, securities or
assets thereafter deliverable upon the conversion of such holder's shares. The
Corporation shall not effect any consolidation, merger or sale, unless the
successor corporation (if other than the Corporation) resulting from such
consolidation or merger or the corporation purchasing such assets shall assume
the obligation to deliver to each such holder such shares of stock, securities
or assets as, in accordance with the foregoing provisions, such holder may be
entitled to acquire or receive.

          5.4 NOTICE OF ADJUSTMENT. Immediately upon any adjustment of the
Conversion Price, the Corporation shall send written notice thereof to all
holders of Series C Preferred Stock, which notice shall state the Conversion
Price resulting from such adjustment and the increase or decrease, if any, in
the number of shares of Common Stock acquirable and receivable upon conversions
of all shares of Series C Preferred Stock held by each such holder, setting
forth in reasonable detail the method of calculation and the facts upon which
such calculation is based.

          5.5 OTHER ADJUSTMENT-RELATED NOTICES. In the event that at any time:

          (a)  the Corporation shall declare a dividend (or any other
     distribution) upon its Common Stock payable otherwise than in cash out of
     earnings or earned surplus;

          (b)  the Corporation shall offer for subscription pro rata to the
     holders of any class of its Common Stock any additional shares of stock of
     any class or other rights;

          (c) there shall be any capital reorganization, or reclassification of
     the capital stock of the Corporation, or consolidation or merger of the
     Corporation with, or sale


                                       9

<PAGE>

     of all or substantially all of its assets to, another corporation; or

          (d)  there shall be any voluntary or involuntary dissolution,
     liquidation, winding up or similar distribution of the Corporation.

     Then, in connection with any such event set forth in (a) through (d) above,
     the Corporation shall give by first class mail, postage prepaid, addressed
     to the holders of Series C Preferred Stock at the address for each such
     holder as shown on the books of the Corporation:

          (i)  at least 30 days' prior written notice of the date on which the
     books of the Corporation shall close or a record shall be taken for such
     dividend, distribution or subscription rights (and specifying the date on
     which the holders of Common Stock shall be entitled thereto) or for
     determining rights to vote in respect of such reorganization,
     reclassification, consolidation, merger, sale, dissolution, liquidation,
     winding up or similar distribution; and

          (ii) in the case of any such reorganization, reclassification,
     consolidation, merger, sale, dissolution, liquidation, winding up or
     similar distribution, at least 30 days' prior written notice of the date
     when the same shall take place (and specifying the date on which the
     holders of Common Stock shall be entitled to exchange their Common Stock
     for securities or other property deliverable upon such reorganization,
     reclassification, consolidation, merger, sale, dissolution, liquidation,
     winding up or similar distribution).

          5.6 NOTICE OF CERTAIN EVENTS. If any event occurs which could be
reasonably expected to negatively affect the conversion rights of the Series C
Preferred Stock then the "Corporation" shall provide written notice to the
Holders of the Series C Preferred Stock of record within thirty days of such
event.

          Section 6. VOTING RIGHTS OF SERIES C PREFERRED STOCK.

          Except as otherwise provided by law, by agreement among the
stockholders, or as otherwise provided in this Certificate of Designations,
Series C Preferred Stock shall entitle the holders thereof to no voting rights.

          Section 7. REGISTRATION OF TRANSFER.


                                       10

<PAGE>

          The Corporation shall keep at its principal office (or such other
place as the Corporation reasonably designates) a register for the registration
of shares of Series C Preferred Stock. Upon the surrender of any certificate
representing Series C Preferred Stock at such place, the Corporation shall, at
the request of the registered holder of such certificate, execute and deliver
(at the Corporation's expense) a new certificate or certificates in exchange
therefor representing the aggregate number of shares represented by the
surrendered certificate, subject to the requirements of applicable securities
laws. Each such new certificate shall be registered in such name and shall
represent such number of shares as shall be requested by the holder of the
surrendered certificate, shall be substantially identical in form to the
surrendered certificate.

          Section 8. REPLACEMENT.

          Upon receipt of evidence reasonably satisfactory to the Corporation
(an affidavit of the registered holder shall be satisfactory) of the ownership
and the loss, theft, destruction or mutilation of any certificate evidencing one
or more shares of the Series C Preferred Stock and, in the case of any such
loss, theft or destruction, upon receipt of indemnity reasonably satisfactory to
the Corporation (provided that if the registered holder is an institutional
investor its own agreement of indemnity, without bond, shall be satisfactory),
or, in the case of any such mutilation, upon surrender of such certificate, the
Corporation shall (at its expense) execute and deliver in lieu of such
certificate a new certificate of like kind representing the number of shares
represented by such lost, stolen, destroyed or mutilated certificate.

          Section 9. RESTRICTIONS ON CORPORATE ACTION.

          The Corporation shall not modify its Restated Certificate of
Incorporation or Bylaws so as to amend or change any of the rights, preferences
or privileges of the Series C Preferred Stock without the consent of the holders
of a majority of the Series C Preferred Stock.

          Section 10. MISCELLANEOUS.

          (a)  The unenforceability or invalidity of any provision or provisions
of this Certificate of Designations shall not render invalid or unenforceable
any other provision or provisions herein contained.

          (b)  Section and paragraph headings herein are for convenience only
and shall not be construed as a part of this Certificate of Designations.


                                       11

<PAGE>

          (c)  All notices to holders of Series C Preferred Stock required or
permitted hereunder shall be sent by overnight courier service, prepaid,
addressed to each such holder at the address for such holder shown on the books
of the Corporation.

          IN WITNESS WHEREOF, this Certificate has been signed on this 28th day
of December, 1998, and the signature of the undersigned shall constitute the
affirmation and acknowledgment of the undersigned, under penalties of perjury,
that this Certificate is the act and deed of the undersigned and that the facts
stated in the Certificate are true.

                                   SERACARE, INC.

                                        By: /s/ Barry D. Plost
                                           ------------------------------------
                                             Barry D. Plost, President

                                   ATTEST:
                                        /s/ Jerry Burdick
                                           ------------------------------------
                                             Jerry L. Burdick,
                                             Executive Vice President


                                       12