Recipient Serum Samples (4/6/94)

Date:     April 6, 1994  
   
From:     Director  
          Division of Field Investigations  (HFC-130)  
   
Subject:  Recipient Serum Samples  
   
To:       Investigations Branch Directors  
   
   
Information:   Regional Food and Drug Directors  
               District Directors  
   
   
21 CFR 606.151(b) states standard operating procedures for
compatibility testing shall include the use of fresh recipient
serum samples less than 48 hours old for all pretransfusion
testing.  The Office of Compliance, Center for Biologics
Evaluation and Research (CBER), has advised DFI that holding  
samples more than 48 hours is not, by itself, objectionable.    
   
The 48 hour timeframe was selected in the 1970s.  During this
period, it was thought that the time limit was needed to assure
that "complement" was present to detect clinically significant
antibodies in the crossmatch procedure.  Following a review of
additional information by the Blood Products Advisory Committee,
CBER issued a guidance memorandum to the blood banking industry
on December 14, 1984 to permit alternative methods for the
antiglobulin phase of the crossmatch. The memorandum addressed
elements of compatibility procedures that would be equivalent to
procedures found in 21 CFR 606.151; however, it did not specify
the age of the sample to be used in a crossmatch.  Although  
the regulation is still in place, CBER does not regard it as a
serious concern.  We anticipate that, through the current
retrospective review of the regulations, this requirement will be
modified to reflect the current standard in the industry, which
is a longer time period.  
   
Establishments must have SOPs setting age specifications for
samples to be used in a crossmatch and criteria to assure the
identity and integrity of the sample(s).  Criteria may include,
but are not limited to, testing serum of patients who have been
pregnant or transfused within three months and infants.  

While there is no upper time limit for use of a sample, we expect
that the firms should have established procedures to ensure
proper controls over use of older samples.  Extended periods of
time for holding test samples should be discussed with CBER, if
encountered.  
   
For further guidance, contact Mary Ann Tourault, OC/CBER,
HFM-655, (301) 594-1191.  



                         Robert C. Fish