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                                                                  EXHIBIT 10.5

                                PROMISSORY NOTE

$90,000                                                 Los Angeles, California
                                                              November 10, 2000

         1.  PRINCIPAL. FOR VALUE RECEIVED, the undersigned, SeraCare, Inc.,
a Delaware corporation ("Maker"), hereby promises to pay to Jerry L. Burdick,
("Holder"), or his/her/its order or successors or assigns, at SeraCare, Inc.,
1925 Century Park East, Suite 1970, Los Angeles, California 90067, or at such
other place as Holder may from time to time designate, in lawful money of the
United States of America, the principal sum of Ninety Thousand dollars
($90,000.00)(the "Principal Sum"), together with interest on the unpaid
balance accrued from the date first written above at a rate equal to ten
percent (10%) per annum, with a minimum interest charge of $900.00, all in
accordance with the terms of this Promissory Note (the "Note").

         2.  In consideration for the loan the Company shall issue to the
Bridge Lender an aggregate of 22,500 warrants to purchase common stock of the
Company (the "WARRANTS"). Each Warrant shall permit the holder to purchase
shares of the Company at an initial purchase price of $3.125 per share and
shall be exercisable for five years. Such Warrants shall contain standard
cashless exercise provisions and shall be in the form attached hereto.

         3.  PAYMENT. Unless sooner accelerated pursuant to the terms of this
Note, interest accrued on the Principal Sum shall become due and payable on
December 10, 2000.

         4.  PREPAYMENT.  Maker may, at any time and from time to time,
without penalty, make prepayments on the Principal Sum.

         5.  EVENT OF DEFAULT.  As used herein, an "Event of Default" shall
be defined as the failure of Maker to make any payment of principal or
interest when due under the terms of this Note, such failure continuing for a
period of thirty (30) calendar days after the due date without being cured.
Upon the occurrence of an Event of Default, the unpaid principal balance of
this Note and all interest accrued thereon may, at Holder's option, at
any time thereafter be accelerated and be declared to be immediately due and
payable.

         6.  INTEREST RATE LIMITATION.  It is the intent of Maker and Holder
that none of the terms and provisions contained herein shall be construed to
create a contract for use, forbearance or detention of money requiring the
payment of interest at a rate in excess of the maximum interest rate
permitted by applicable law. If any Holder of this Note shall collect monies
which are deemed to constitute interest which would otherwise increase the
effective interest rate of this Note to a rate in excess of the maximum rate
permitted to be charged by

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applicable law, all such sums deemed to constitute interest in excess of such
maximum rate shall, at the option of Holder, be credited to the payment of
the sums due hereunder or returned to Maker.

         7.  SECURITY.  This Note shall be secured by all of the assets,
tangible and intangible, of Maker set forth on Exhibit A hereto.

         8.  WAIVER.  No delay or omission on the part of Holder hereof in
exercising any right under this Note shall operate as a waiver of such right.
Moreover, a waiver of any term or condition contained under this Note by
Holder must be in writing to be effective and shall not be construed as a
waiver of any subsequent breach or failure of the same term or condition or
of any other term or condition contained in this Note.

         9.  AMENDMENTS.  Neither this Note nor any provision hereof may be
changed, waived, discharged or terminated orally, but only by an instrument
in writing signed by the party against whom enforcement of the change,
waiver, discharge or termination is sought.

         10.  SUCCESSORS.  This Note shall be binding upon and inure to the
benefit of the parties hereto and their respective successors and permitted
assigns. Maker may not assign or transfer all or any part of its rights or
obligations hereunder.

         11.  COSTS OF COLLECTION.  Maker promises to pay all costs and
expenses, including reasonable attorney's fees, incurred in connection with
the collection and enforcement of this Note. Maker hereby waives diligence,
presentment, protest, demand and notice of every kind, to the fullest extent
permitted by law, and the right to plead any statute of limitations as a
defense to any demand hereunder.

         12.  GOVERNING LAW.  This Note shall be governed by, and construed
and enforced in accordance with, the laws of the State of California,
without regard to conflicts of laws principles.

         13.  DRAFTING.  Maker hereby waives the benefit of any statute or
rule of law or judicial decision, which would otherwise require that the
provisions of this Note be construed or interpreted most strongly against the
party responsible for the drafting thereof.

         14.  SEVERABILITY.  If any provision of this Note is held to be
unenforceable for any reason, it shall be adjusted rather than voided, if
possible, to achieve the intent of the parties to the extent possible. In any
event, if any term of this Note, or the application thereof to any person,
entity or circumstance, shall, to any extent, be invalid or unenforceable, the
remainder of this Note, or the application of such term to persons, entities
or circumstances other than those as to which it is invalid or unenforceable,
shall not be affected thereby, and each term of this Note shall be valid and
enforceable to the fullest extent permitted by law.

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         15.  HEADINGS.  Headings at the beginning of each numbered paragraph
of this Note are intended solely for convenience and are not to be deemed or
construed to be part of this Note.

         16.  ENTIRE AGREEMENT.  This Note sets forth the entire agreement
and understanding of the parties with respect to the subject matter hereof
and supersedes all prior agreements, arrangements and understandings with
respect to the subject matter hereof. No representation, promise, oral or
written agreement, understanding, inducement or statement of intention has
been made by Maker or Holder with respect to this Note which is not embodied
in this Note. Neither Maker nor Holder shall be bound by or liable for any
alleged representation, promise, oral or written agreement, understanding,
inducement or statement of intention with respect to this Note not so set
forth.

         IN WITNESS WHEREOF, the undersigned has executed this Note as of the
day and year first written above.

                                             MAKER:
                                             ------

                                             SERACARE, INC.,
                                             AN DELAWARE CORPORATION

                                                 /S/BARRY D. PLOST
                                             -------------------------
                                             BY:    BARRY D. PLOST
                                             TITLE: PRESIDENT

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                             LIST OF OMITTED EXHIBITS

The following Exhibit to the Secured Promissory Note between SeraCare, Inc.
("Maker") and Jerry L. Burdick ("Holder") in the amount of $90,000, dated
November 10, 2000, has been omitted from this Exhibit and shall be furnished
supplementally to the Commission upon request:

Exhibit A         Secured Assets<PAGE>
                                                           Exhibit 10.6

              The securities represented hereby have not been registered
         under the Securities Act of 1933, as amended, or any state securities
         laws and neither the securities nor any interest therein may be
         offered, sold, transferred, pledged or otherwise disposed of except
         pursuant to an effective registration statement under such Act and
         such laws or an exemption from registration under such Act and such
         laws which, in the opinion of counsel for the holder, which
         counsel and opinion are reasonably satisfactory to counsel for this
         corporation, is available.

                                      NOTE

$200,000.00                                                February 16, 2001

         For value received, the undersigned, SERACARE, INC., a Delaware
corporation having an address at 1925 Century Park East, Suite 1970, Los
Angeles, Ca 90067 (the "BORROWER"), hereby promises to pay to the order of
Dr. Nelson Teng, 24 Bluebell Lane, Hillsborough, CA 94010 (the "PAYEE"), the
principal sum of Two Hundred Thousand Dollars ($200,000.00), on March 30,
2001, together with all accrued interest through and including the date of
payment (the "INITIAL MATURITY DATE"). At the option of the Borrower, the
Maturity Date may be extended through and until May 14, 2001 (the "FINAL
MATURITY DATE"). Interest shall be payable at a rate per annum (computed for
actual days elapsed on the basis of a 365-day year) of twelve percent
(12.0%). The Borrower may prepay this Note at any time prior to the due date
hereof, in full, without premium or penalty.

         Payments of both principal and interest on this Note are to be
made at 24 Bluebell Lane, Hillsborough, CA 94010, or such other place as the
holder hereof shall designate to the Borrower in writing, in lawful money of
the United States of America in immediately available funds.

         The Borrower shall pay reasonable costs and expenses of collection,
including, without limitation, reasonable attorneys' fees and disbursements
in the event that any action ,suit or proceeding is brought by the holder
hereof to collect this Note and either the holder obtains a judgment in its
favor that is not appealed from or is upheld on appeal, or such action, suit
or proceeding is settled with any sum due and owing to the holder as a result
of such settlement.

         THIS NOTE SHALL BE GOVERNED BY, AND CONSTRUED AND ENFORCED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF CALIFORNIA WITHOUT REGARD TO ITS
RULES PERTAINING TO CONFLICT OF LAWS.

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         THE BORROWER IRREVOCABLY CONSENTS THAT ANY LEGAL ACTION OR
PROCEEDING AGAINST IT UNDER, ARISING OUT OF OR IN ANY MANNER RELATING TO THIS
NOTE MAY BE BROUGHT IN ANY COURT OF THE STATE OF NEW YORK, COUNTY OF NEW
YORK, OR IN THE UNITED STATES DISTRICT COURT FOR THE STATE OF NEW YORK OR IN
THE STATE OF CALIFORNIA, OR IN THE UNITED STATES DISTRICT COURT FOR THE STATE
OF CALIFORNIA. THE BORROWER, BY THE EXECUTION AND DELIVERY OF THIS NOTE,
EXPRESSLY AND IRREVOCABLY ASSENTS AND SUBMITS TO THE PERSONAL JURISDICTION OF
ANY OF SUCH COURT IN ANY SUCH ACTION OR PROCEEDING. BY ITS ACCEPTANCE OF THIS
NOTE BY THE HOLDER AND BY THE EXECUTION HEREOF BY THE BORROWER, EACH AGREES
THAT ANY AND ALL LEGAL ACTION RELATING TO THIS NOTE SHALL BE BROUGHT, AND
MAINTAINED, ONLY IN SUCH COURTS. THE BORROWER FURTHER IRREVOCABLY CONSENTS TO
THE SERVICE OF ANY COMPLAINT, SUMMONS, NOTICE OR OTHER PROCESS RELATING TO
ANY SUCH ACTION OR PROCEEDING BY DELIVERY THEREOF TO IT AT THE ADDRESS SET
FORTH ABOVE OR SUCH OTHER ADDRESS AS THE BORROWER SHALL HAVE THERETOFORE
NOTIFIED THE HOLDER HEREOF IN WRITING OR IN ANY OTHER MANNER PERMITTED BY
LAW. IN THE EVENT SERVICE ON THE BORROWER IS EFFECTED AS SET FORTH IN THE
PRECEDING SENTENCE, THE BORROWER HEREBY EXPRESSLY AND IRREVOCABLY WAIVES ANY
CLAIM OR DEFENSE IN ANY SUCH ACTION OR PROCEEDING BASED ON ANY ALLEGED LACK
OF PERSONAL JURISDICTION, IMPROPER VENUE, FORUM NON CONVENIENS, OR ANY
SIMILAR BASIS.

                                       SERACARE, INC.

                                       By: /s/Jerry L. Burdick
                                         ----------------------

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