HOW ACCURATE IS SEROLOGIC TESTING OF PLASMA POOLS FOR HEPATITIS-B VIRUS SURFACE-ANTIGEN, ANTI-HUMAN-IMMUNODEFICIENCY-VIRUS-1 AND ANTI-HUMAN-IMMUNODEFICIENCY-VIRUS-2, AND ANTI-HEPATITIS-C-VIRUS

Objective: The European pharmacopeia prescribes that. during the manuf acture of blood derivates, the first homogeneous pool of plasma (for e xample, after removal of cryoprecipitate) must be tested for hepatitis B virus surface antigen (HBsAg), for hepatitis C virus (HCV) antibodi es and for human immunodeficiency virus (HIV) antibodies using test me thods of suitable sensitivity and specificity. in order to reduce the residual risk of infection originating from blood products The present study was performed to verify if commercially available immunoassays, which are licensed for the screening of single serum and plasma sampl es, are suitable for the determination of HBsAg, anti-HCV, and anti-HI V in plasma pools Design: Plasma pools originating from different coun tries were spiked with HBsAg- and anti-HCV-positive standards (Nationa l Institut fur Biological Standards, Hertfordshire, UK) and anti-HIV-p ositive serum. For the determination of HBsAg with and without immune complex dissociation (ICD), anti-HCV and anti-HIV antibodies the Abbot t (Delkenheim, Germany) IMx system was used. Results: In contrast to t he testing for anti-HIV and anti-HCV, the detection of HBsAg (0.125 IU /ml detection limit) was influenced by the presence of anti-HBs in pla sma pools. Statistically significant differences could be observed bet ween anti-HBs-positive plasma pools and anti-HBs-negative serum sample s spiked with HBsAg. The kinetics of HBsAg-anti-HBs complex formation showed that in a plasma pool with a high anti-HBs (329.4 IU/ml) concen tration HBsAg was not delectable after 5 h of incubation. After ICD, H BsAg was still detectable in the pool with high anti-HBs content. Anti -HIV antibodies could be detected up to a dilution of 1/480,000, anti- HCV up to a dilution of 1/80, both in a spiked negative serum. Overall , the divergences between spiked plasma and serum were relatively low for anti-HCV and anti-HIV detection. Conclusions: The Abbott IMx assay permits a highly sensitive detection of HBsAg (after ICD or immediate ly after thawing of anti-HBs-positive plasma pools), anti-HCV, and ant i-HIV in plasma pools. However, in case of a contamination with donati ons originating from individuals with acute HBV, HIV, or HCV infection or with a poor humoral immune response, serologic testing for HBsAg, anti-HIV, and anti-HCV may fail to detect potentially infectious plasm a pools.