SCREENING WITH COST-EFFECTIVE QUALITY-CONTROL - POTENTIAL APPLICATIONS TO HIV AND DRUG-TESTING

This article investigates the applicability of group testing as a qual ity control procedure to monitor the sensitivity of screening tests us ed to check the blood supply for infective agents or to check employee s for drug use. The problem is important, as the accuracy of screening tests in the field may deteriorate over time. In the blood screening application, our results demonstrate that group testing the screened n egatives provides a procedure with high power to detect a decline of . 02 in the sensitivity of the original test when the prevalence in the population is quite low (.0001). Moreover, the procedure is cost-effec tive in the sense that the expected cost per human immunodeficiency vi rus (HIV) infection avoided could be less than $1 million, in contrast to much higher economic valuations of life that are used in regulator y analyses. The statistical properties of estimates of the prevalence, as well as those for the sensitivity and specificity of the screening test using the extra information obtained from the quality control pr ocedure, are also presented.