The Ausria Test: Critical Evaluation of Sensitivity and Specificity

Ausria was shown to be considerably more sensitive than CEP by comparing titers of HBAg+ sera and by testing selected proficiency panels, sera from hepatitis patients, and sera from experimentally infected rhesus monkeys; CEP+, Ausria-sera were never encountered. However, in testing NIH donors and personnel, 19 of 20 Ausria+, CEP-sera were shown by neutralization studies to be nonspecific for HBAg, i.e., false positives. Nonspecificity was confirmed by an alternate radioimmunoassay procedure and, in one serum, by density-gradiant ultracentrifugation. Testing of 35 additional Ausria+, CEP-sera from New Jersey donors showed 13 specific and 22 (63%) nonspecific reactions. It is mandatory that serum from every Ausria+, CEP-donor undergo specificity testing. In addition to the 14 specific Ausria+, CEP-sera, two sera, subsequently shown to be CEP+, were undetected on the initial CEP test (one was transfused and resulted in hepatitis). These sera were strongly positive by Ausria; sera subject to reader error in CEP are unequivocally positive by Ausria. Ausria tests on CEP-donors suspected of transmitting HBAg failed to implicate a donor in each of eight cases. Some HBAg+ hepatitis will continue to occur despite universal application of Ausria or other tests of equal sensitivity.