EXHIBIT 5


                       [O'Melveny & Myers LLP Letterhead]

November 19, 2003

SeraCare Life Sciences, Inc.
1935 Avenida del Oro, Suite F
Oceanside, California  92056

  Re:  Registration on Form S-8 of SeraCare Life Sciences, Inc. (the "Company")

Gentlemen:

     In connection with the registration of up to 1,000,000 shares of Common
Stock of SeraCare Life Sciences, Inc., a California corporation (the "Company"),
no par value per share (the "Shares"), under the Securities Act of 1933, as
amended (the "Act"), pursuant to a Registration Statement on Form S-8 (the
"Registration Statement"), filed with the Securities and Exchange Commission on
or about the date hereof, such Shares to be issued or delivered pursuant to the
SeraCare Life Sciences, Inc. 2001 Stock Incentive Plan (the "Plan"), you have
requested our opinion set forth below.

     In our capacity as such counsel we have examined originals or copies of
those corporate and other records of the Company we considered appropriate.

     On the basis of such examination and our consideration of those
questions of law we considered relevant, and subject to the limitations and
qualifications in this opinion, we are of the opinion that the Shares have been
duly authorized by all necessary corporate action on the part of the Company and
when issued in accordance with such authorization, the provisions of the Plan
and relevant agreements duly authorized by and in accordance with the terms of
the Plan and, upon payment for and delivery of the Shares as contemplated in
accordance with the Plan, and either (a) the countersigning of the certificate
or certificates representing the Shares by a duly authorized signatory of the
registrar for the Company's Common Stock, or (b) the book-entry of the Shares by
the transfer agent for the Company's Common Stock in the name of The Depository
Trust Company or its nominee, the Shares will be validly issued, fully paid and
non-assessable.

     We consent to your filing this opinion as an exhibit to the Registration
Statement.

                                   Respectfully submitted,

                                   /s/ O'MELVENY & MYERS LLP