Document:

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                                                                Exhibit 10.28

                                                             REDACTED VERSION

                             PLASMA SUPPLY AGREEMENT

     *** Confidential treatment has been requested as to certain portions of
     this agreement. Such omitted confidential information has been
     designated by an asterisk and has been filed separately with the
     Securities and Exchange Commission pursuant to Rule 24b-2 under the
     Securities Exchange Act of 1934, as amended, and the Commission's rules
     and regulations promulgated under the Freedom of Information Act,
     pursuant to a request for confidential treatment.***

In Los Angeles on this 23rd day of October, 1997.

                                 BY AND BETWEEN

SERACARE Inc., a corporation of U.S.A. nationality, with address at
1925 Century Park East, Suite 1970, Los Angeles, California, U.S.A.,
represented by Mr. Barry D. Plost, by virtue of his position as Chairman
(CEO) (Hereinafter referred to as SERACARE), party of the first part.

INSTITUTO GRIFOLS, S.A., a corporation of Spanish nationality, with address
at Poligono Industrial Levante, Calle Can Guasch, s/n. 08150 Parets del
Valles, Barcelona, Spain, represented by Mr. Javier Jorba Ribes, by virtue of
his position as General Manager, (Hereinafter referred to as GRIFOLS), party
of the second part.

                                    WHEREAS

I.     SERACARE is a corporation, which main activity is the collection of
Human Source Plasma, through donations carried out in its Plasma Centers
located in the U.S.A.

II.    GRIFOLS is a corporation, which main activity is the manufacturing and
commercialization of Hemoderivatives, which are manufactured in its premises
located at Parets del Valles.

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III.   SERACARE, declares that its Plasma Centers comply with all legal
requirements and/or regulations of the authorities in the U.S.A., in special
from the Health Authorities and the Food and Drug Administration (FDA), and
have all the necessary and required permits.

IV.    SERACARE is willing to supply and GRIFOLS to obtain, Human Source
Plasma (hereinafter referred to as Plasma), due to which, both parties
recognizing in each other enough legal capacity, agree to enter into the
present Plasma Supply Agreement in accordance with the following:

                                  CLAUSES

       FIRST - Constitutes the object of the present Agreement, the supply of
Human Source Plasma obtained from the Plasma Centers of SERACARE within the
U.S.A., done by this to GRIFOLS, in accordance with the provisions of this
Agreement.

       SECOND - Due to the special technical specifications and quality
controls that the Plasma has to comply with, the parties agree that all the
Plasma supplied from SERACARE to GRIFOLS, will be exclusively obtained from
the Plasma Centers which are detailed in Annex I to the present.

       SERACARE shall immediately inform GRIFOLS of any fault findings,
quality deviations, etc., that have been found at SERACARE's Centers by
Governmental or Health Authorities and advise GRIFOLS if Plasma sent to
GRIFOLS is affected by such deviations.

       THIRD - GRIFOLS shall have the right to inspect the Plasma Centers
from which SERACARE obtains the Plasma that is supplied to GRIFOLS. This
inspections will include the right to visit production facilities and review
donor records.

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       GRIFOLS, shall also have the right, if it is requested by this, to
obtain authorization from SERACARE so that any Health Authorities may visit
and inspect the Plasma Centers from which SERACARE obtains the Plasma that is
supplied to GRIFOLS.

       FOURTH - GRIFOLS will purchase from SERACARE the annual minimum amount
of *** liters of Plasma for the year ending on 31st December 1997, and ***
liters for the year ending on 31st December 1998, in shipments of between ***
and *** liters each.

       The above quantities shall be provided from the Plasma Centers which
are detailed in Annex I.

       FIFTH - The quality and technical specifications of the Human Source
plasma supplied by SERACARE to GRIFOLS, are detailed in Annex II, which as
well includes all the required tests to which said plasma has to be submitted.

       SERACARE will be responsible for the "Inventory Hold" of the Plasma,
that for year 1997 will be of 30 days and for year 1998 will be of 60 days,
which means that in both cases delivery cannot be made before such term
expires.

       The quality and technical specification, may be changed and/or
modified, at Grifols' requirement, in order to comply with any new
legislation in force and/or new controls or test methods which are available
in order to obtain the most secure Plasma possible.

       Every shipment of Plasma, will be shipped together with all the
mandatory and/or legal documents, as well as any other documents that may be
required by GRIFOLS.

----------------------------
*** Confidential information omitted and filed separately with the Securities
and Exchange Commission.

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       SIXTH - GRIFOLS will pay to SERACARE US$ *** per liter of plasma, said
price including the applicable Incoterms, which are CIP (Carriage and
Insurance Paid to) Parets del Valles.

       In the event that / new test and/or control is required, as stated in
Clause Fifth hereinabove, GRIFOLS and SERACARE shall mutually agree to
renegotiate the prices set forth in this Agreement.

       SEVENTH - Payment of the Plasma delivered by SERACARE to GRIFOLS would
be payable 30 days after reception by GRIFOLS in its premises in Parets del
Valles.

       EIGHT - The Plasma will be shipped and packed in accordance with the
specifications set forth in Annex III to the present, and will contain the
samples of each plasma unit for evaluation and approval which are also
detailed in said Annex III.

       NINTH - For the event that a shipment of Plasma and/or the units of
Plasma do not comply with the specifications agreed herein, SERACARE will be
responsible and shall reimburse of all costs, including the price, incurred
by GRIFOLS.

       The same will be of application for the event of "look backs" due to
seroconversions of the donors, and as well as for any other reason that makes
the units of Plasma not suitable to be processed.

       TENTH - The duration of the present Agreement will be until ***,
and will start on the date the Plasma Master File is approved by the Health
Authorities, which should occur within 3 months after delivery by SERACARE to
GRIFOLS of the necessary

---------------------------------------
*** Confidential information omitted and filed separately with the Securities
and Exchange Commission.

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documentation. The Agreement will be automatically renewed for one year
periods if neither party denounces it three months before the expiry.

       ELEVENTH - Neither party shall be liable for non-performance of this
Agreement due to Force Majeure. Force Majeure will have the meaning stated
below under (a):

              (a) Strikes, lockouts, other industrial disturbances,
rebellions, mutinies, epidemics, landslides, lightning, earthquakes, fires,
storms, floods, sinking, drought, civil disturbances, explosions, act or
decisions of duly constituted municipal, state or National Governmental
Authorities or of Courts of Law, impossibility to obtain supplies, fuel or
other required materials; or any other causes similar or completely
different, all beyond the control of the party pleading Force Majeure
preventing the Party from performing its rights and obligations and not to be
overcome by due diligence of such Party.

              (b) The parties agree that if either of them find themselves
wholly or partly unable to fulfill their respective obligations in this
Agreement by reasons of Force Majeure, the Party pleading Force Majeure will
as soon as possible notify the other Party of its inability to perform giving
a detailed explanation of the occurrence which excuses performance. If said
notice is given, the performance of the notifying party shall be abated for
so long as performance may be prevented by Force Majeure. A Party unable to
perform due to Force Majeure shall resume fulfilling its obligations,
including making the due payments, after the Force Majeure has ceased. All
terms will be extended by the time period the Force Majeure has lasted.

       TWELFTH - The present Agreement will be terminated and will become
null due to any of the following reasons:

              (a) Mutual agreement

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              (b) Those fixed by Law.

              (c) With thirty (30) days notice if the other party shall
default in the performance or observation of any material provisions of this
Agreement and shall fail to cure such default within sixty (60) days after
notice from such party, and the non-defaulting party shall reserve a right to
seek a remedy available under the applicable laws.

              (d) If any party falls into a suspension of payments or becomes
bankrupt.

              (e) Not meeting payments due.

              (f) Any substantial change in the ownership in any of the
parties which may give rise to a change in the political control of the
Company, or the participation through the acquisition of shares by a direct
competitor of any of the parties.

       THIRTEENTH -

              (a) Any notice required or provided for by the terms of this
Agreement shall be made in writing and shall be sent by registered air mail
postage prepaid or by telex or by facsimile properly addressed in accordance
with the addresses first above given or to such other addresses as the
parties may at a later date advise. The effective date of the notice shall be
six (6) days after the date of sending such notice.

              (b) This Agreement constitutes the entire agreement between the
parties concerning the subject matter hereof. None of the terms of this
Agreement shall be amended or modified except in writing signed by the
parties hereto. The headings used in this Agreement are only meant for easy
reading of the Agreement.

              (c) Provisions of this Agreement are separate and divisible
and the invalidity or unforceability of any part shall not affect the
validity or enforceability of any remaining part

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or parts, all of which remain in full force and effect. However, the parties
agree to substitute any invalid or unenforceable provision by valid and
enforceable arrangement which achieves to the greatest extent possible the
financial balance and actual understanding already established between the
parties.

       FOURTEENTH - Any dispute, controversy or difference that may arise
from the interpretation or in connection with the present Agreement or as the
compliance of any other obligations contained herein, shall be submitted to
arbitration held in Barcelona (Spain), in the "Tribunal Arbitral de
Catalanya" according to its rules. The award rendered in any such arbitration
shall be legal and binding upon the parties hereto.

       FIFTEENTH - The parties agree that the present document is a
commercial agreement and is ruled by the Clauses contained herein, and shall
be governed by the laws of Spain, by Spanish commercial usage or, in its
case, by the Spanish Civil Code.

       IN WITNESS WHEREOF, the present Agreement is singed in duplicate in
the place and date first written above.

INSTITUTO GRIFOLS, S.A.                SERACARE, INC.

/s/ Javier Jorba Ribes                 /s/ Barry Plost
-----------------------------          -----------------------------

                                       7<PAGE>

                                                                Exhibit 10.28.1
                                                               REDACTED VERSION

                           PLASMA SUPPLY AGREEMENT
                            DATED 23 OCTOBER 1997
                               AMENDMENT NR. 1

        *** Confidential treatment has been requested as to certain portions
        of this agreement. Such omitted confidential information has been
        designated by an asterisk and has been filed separately with the
        Securities and Exchange Commission pursuant to Rule 24b-2 under the
        Securities Exchange act of 1934, as amended, and the Commission's rules
        and regulations promulgated under the Freedom of Information Act,
        pursuant to a request for confidential treatment. ***

In Los Angeles, this ____ day of ___________, 1998.

                                BY AND BETWEEN

        Seracare Inc., a corporation of USA nationality, with address at 1925
Century Park East, Suite 1970, Los Angeles, California, USA, represented by
Mr. Barry D. Plost, by virtue of his position as Chairman/CEO (hereinafter
referred to as Seracare), party of the first part.

        Instituto Grifols, S.A., a corporation of Spanish nationality, with
address at Poligono Industrial Levante, calle Can Guasch, s/n, 08150 Parets
del Valles, Barcelona, Spain, represented by Mr. Javier Jorba Ribes, by
virtue of his position as General Manager (hereinafter referred to as
Grifols), party of the second part.

                                    WHEREAS

        The parties have signed a Plasma Supply agreement dated 23 October
1997, and wish to amend said Agreement in accordance with the following:

                                    CLAUSES

        FIRST.--Grifols will purchase from Seracare the annual minimum amount
of *** litres of plasma for the year ending on 31 December 1999, in shipments
of between *** and *** litres each.

        SECOND.--Grifols shall have the option for year ending 31 December
2000 to purchase from Seracare *** litres of plasma. This option must be
exercised by Grifols by giving a 90-day prior written notice before 31
December 1999.

______________________
*** Confidential information omitted and filed separately with the Securities
and Exchange Commission.

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        Grifols also has the option to reduce the agreed amount of *** litres
by ***, i.e. to *** litres. If Grifols decides to exercise this option, it
must provide Seracare with a 90-day prior notice in writing before 31
December 2000, all other terms and conditions remaining the same.

        THIRD.--Seracare will provide blood grouping in all plasma units
delivered to Grifols.

        FOURTH.--Grifols will pay to Seracare US$ *** per litre of plasma
delivered during the validity of present Agreement, also applicable for the
optional period. This price includes the applicable INCOTERMS, which are CIP
(Carriage and Insurance Paid to) Parets del Valles.

        FIFTH.--Grifols policy is to have more than one plasma supplier,
therefore in the event that Seracare enters into a merger, acquisition, or
any procedure by which it becomes controlled or part of a business and/or
enterprise in a way that Grifols has only one supplier, Grifols at its option
may terminate the present Plasma Supply Agreement by giving written prior
notice of 30 days after becoming aware of this new circumstance.

        SIXTH.--The present amendment is intended by both parties hereto as
an extension of the term of the original Plasma Supply Agreement dated 23
October 1997, which will be extended until ***, as well as a modification to
all other terms and conditions including in the present document.

        All terms and conditions of the original Plasma Supply Agreement
shall remain in full force and effect except for those amended herein.

        IN WITNESS WHEREOF, the present Agreement is signed in duplicate in
the place and date first written above.

INSTITUTO GRIFOLS, S.A.                         SERACARE INC.

/s/ Javier Jorba Ribes                          /s/ Barry Plost
General Manager                                 Chairman / CEO

______________________
*** Confidential information omitted and filed separately with the Securities
and Exchange Commission.

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