Summary: This article investigates the applicability of group testing as a quality control procedure to monitor the sensitivity of screening tests used to check the blood supply for infective agents or to check employees 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 negatives provides a procedure with high power to detect a decline in .02 in the sensitivity of the original test when the prevalence in the population is quite low (.0001).
Moreover, the procedure is cost-effective in the sense that the expected cost per human immunodeficiency virus (HIV) infection avoided could be less than \(\$1\) million, in contrast to much higher economic valuations of life that are used in regularity 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 procedure, are also presented.