Sensitivities of radioimmunoassay and enzyme-linked immunosorbent assay for detection of hepatitis B surface antigen

Inhibition ELISA for hepatitis B surface antigen (HBsAg) using monoclonal idiotype-anti-idiotype interaction

Monoclonal anti-idiotypic antibody (Anti-Id) to the common (a) epitope of hepatitis B surface antigen (HBsAg) were raised and used to detect serum HBsAg in an inhibition enzyme-linked immunosorbent assay (inhibition ELISA). HRP-labelled Id 8D-3-6 was reacted with Anti-Id 4-8H coated on the solid phase in the presence of HBsAg. The ability of the antigen to inhibit the binding of labelled Id 8D-3-6 to anti-Id 4-8H was determined and the results correlated well with those obtained by radioimmunoassay. This assay requires only one washing step, takes 2 h and covers the range 10 ng/ml to 1 microgram HBsAg/ml. The inhibition ELISA is a more convenient, rapid and relatively sensitive assay which can be used to measure the level of a wide range of serum HBsAg.

Evaluation of a semi-automatic radioimmunoassay for hepatitis B surface antigen (HBsAg)

The recently developed semi-automatic Hepatube system was evaluated in comparison to another radioimmunoassay for the detection of hepatitis B surface antigen (HBsAg), the manual Ausria II-125 test. After incubation of serum in anti-HBs coated tubes, the Hepatube system uses a machine to wash the tubes and to add tracer. After a second incubation, tubes are washed again in the machine and are manually transferred to the gamma counter. Two machines were used. Machine 1 had an undefined defect. Of 1490 samples tested, 69 (4.6%) gave false-positive results versus 11 (0.7%) in the Ausria II-125 test. Machine 2 had one false-positive result among 920 samples versus 5 in the Ausria II-125 test. The sensitivity was measured with reference panels from Wellcome and Abbott as well as in titration series. The Hepatube system was found to be a factor three less sensitive than the Ausria II-125 test. The Hepatube processor is easy to handle; radioactive material can be held at a distance during the whole procedure; waste material is limited and less voluminous than in the Ausria II-125 test.

Comparison of sic 'Third-Generation' tests for the detection of HBsAg

Six 'third-generation' techniques for the detection of HBsAg were compared, i.e. Ausria II-125, Travenol-RIA, Auszyme, Hepanostika, Auscell and a modified Auscell technique applying centrifugation instead of sedimentation. The Ausria II-125 was the most sensitive test, followed by Travenol-RIA, both Auscell techniques, Auszyme and Hepanostika. In the Ausria II-125, Hepanostika and Auscell techniques, 1-2% of false-positive results were found in serum and 2% in plasma specimens from blood donors. Both the Travenol-RIA and Auszyme tests gave an unacceptably high percentage (6-8%) of false-positive results in both serum and plasma specimens.