AGREEMENT Agreement, dated June 20, 2001. Each of Grupo Grifols, S.A., Instituto Grifols, S.A. and SI Merger Corp. agree to the filing of a single statement on Schedule 13D on behalf of each of them in respect of the common stock of SeraCare, Inc....

                                                                    EXHIBIT 99.5


                                    AGREEMENT

      Agreement, dated June 20, 2001. Each of Grupo Grifols, S.A., Instituto
Grifols, S.A. and SI Merger Corp. agree to the filing of a single statement on
Schedule 13D on behalf of each of them in respect of the common stock of
SeraCare, Inc. beneficially owned by them.

      IN WITNESS WHEREOF, the undersigned have executed this agreement as of the
date first above written.


                                     GRUPO GRIFOLS, S.A.


                                     By:   /s/ Xxxxxx Grifols Xxxxx
                                           ------------------------
                                           Xxxxxx Grifols Xxxxx
                                           Chief Executive Officer

                                     INSTITUTO GRIFOLS, S.A.


                                     By:   /s/ Xxxxxx Grifols Xxxxx
                                           ------------------------
                                           Xxxxxx Grifols Xxxxx
                                           Chief Executive Officer

                                     SI MERGER CORP.


                                     By:   /s/ Xxxxxx Grifols Xxxxx
                                           ------------------------
                                           Xxxxxx Grifols Xxxxx
                                           President