Specificity and sensitivity of radioimmunoassay for hepatitis B antigen.
Sera from a survey of 6,026 people were tested for hepatitis B surface antigen by using radioimmunoassay and counterelectrophoresis. Forty-eight sera (0.79%) were positive by counterelectrophoresis and 152 sera (2.52%) were positive by radioimmunoassay, using the most liberal of the recommended criteria for positivity (i.e., counts 3 standard deviations above the mean). Absorption tests performed on the 152 radioimmunoassay-positive sera showed that 10 (6.6%) were false-positive reactions to guinea pig protein, 74 (48.6%) were due to false-positive reaction(s) with other protein(s) in the test system, and 68 (44.8%) were true positives. There was a strong correlation between the degree of elevation of radioactive counts and the proportions of sera that were true positives; all 49 sera with counts >50 standard deviation units above the mean were true positives, but only 19 (18.4%) of the 103 sera with counts <50 standard deviation units were true positives. A few sera with high counts required absorption with type-specific (type D) antisera. The following conclusions were reached from this study: (i) absorption tests should be run on all radioimmunoassay-positive, counterelectrophoresis-negative sera; (ii) most (about 90%) false positives are not due to anti-guinea-pig protein reactions; and (iii) radioimmunoassay, in combination with absorption tests, yields a modest increase (about 35%) in detection of true positives over use of counterelectrophoresis alone.
D000818:Animals; D000937:Antigen-Antibody Reactions; D005069:Evaluation Studies as Topic; D006168:Guinea Pigs / Q000276:immunology; D006382:Hemadsorption; D006506:Hepatitis A / Q000276:immunology; D006511:Hepatitis B Antigens / Q000032:analysis*; D006801:Humans; D007106:Immune Sera; D007122:Immunoelectrophoresis; D007457:Iodine Radioisotopes; D011817:Rabbits / Q000276:immunology; D011863:Radioimmunoassay / Q000592:standards*; D013781:Texas
D006511:Hepatitis B Antigens; D007106:Immune Sera; D007457:Iodine Radioisotopes