Which techniques should be used to screen blood donations for hepatitis B surface antigen?

Haemagglutination assay for HBsAg -- a new approach to reagent preparation

Human group O rhesus negative erythrocytes were spherocyted and fixed in glutaraldehyde, then coated initially with HBsAg and subsequently with anti-HBs. The resulting reagent was found to agglutinate in the presence of HBsAg positive serum, but not in HBsAg negative serum. The assay was evaluated for blood donor screening (39,962 donations) over a 6-month period, and was compared with Hepatest (RPHA) and AUSRIA-2 (RIA) for the study of two established HBsAg panels.

Development of hemagglutination assays II. Enhancement in the sensitivity of an RPHA test for HBsAg

Studies were undertaken to enhance the sensitivity of a previously developed RPHA test for HBsAg. A net increase in sensitivity of approximately 3-fold was achieved by modifying the elution procedure used to purify chimpanzee anti-HBs by affinity chromatography. A further 3- or 4-fold sensitivity increase was achieved by increasing the volume of specimen tested. A concomitant increase in nonspecific agglutination usually observed with increased specimen size was avoided by incubating the reaction mixture at 37 or 45 degrees C. Evaluation of the test in detection of HBsAg in blood obtained from volunteer donors indicates that the materials produced at the New York Blood Center using the modified test protocol compare favorably with a commercial RPHA test. Modifications which did not contribute toward enhancing sensitivity are also reported.

A comparison of different methods of screening blood donations for HBsAg

In a retrospective comparison between countermigration immunoelectrophoresis (CIEP) and reverse passive haemagglutination (RPHA) for screening 260,500 blood donations, the latter's 10-fold increase in sensitivity resulted in 36% more HBsAg detections. In a prospective comparison between RPHA and radioimmunoassay (RIA) the latter's 40-fold increase in sensitivity over RPHA resulted in 11% more detections than RPHA in 27,094 new donors. One in 500 new donors was HBsAg-positive by RPHA, compared with 1 in 11,000 established donors who had donated and been tested previously. Acute hepatitis B infections, though uncommon, accounted for a greater proportion of the HBsAg-positive found in "established" rather than new donors. Reported post-transfusion hepatitis cases have declined following the introduction of screening tests in 1971. The feasibility of RIA testing at a transfusion centre supplied simply with the two basic RIA reagents has been demonstrated.

Evaluation of three reverse passive haemagglutination methods and two radioimmunoassay tests to be used for the detection of hepatitis B surface antigen

Sensitivity and specificity of three reverse passive haemagglutination (RPHA) methods (Hepanosticon, Hepatest and Auscell) and of two solid-phase radioimmunoassays (RIA) (Austria-125 and Ausria II-125), all phase 3 tests for hepatitis B surface antigen (HBSAg), were compared with the sensitivity and specificity of an immunoelectroosmophoresis (IEOP) technique. By titration experiments the RPHA methods were shown to be 5-20 times more sensitive than the IEOP test, while RIA detected 5-10 times lower concentrations of antigen than the most sensitive RPHA test. In a study of sera drawn consecutively from patients with hepatitis B infections, the increased sensitivity of the test methods was according to the following order: IEOP, Hepanosticon, Hepatest, Ausria-125, Auscell, Ausria II-125. There were significant differences between all the methods except for that between Ausria-125 and Auscell. IEOP did not detect any false positives. If, however, RPHA tests were used, the incidence of nonspecific positive reactions would be in the range 0.5%-0.9%. The advantages of the individual test methods are discussed.