Comparison of Murex Single-Use Diagnostic System with Traditional Enzyme Immunoassay for Detection of Exposure to Human Immunodeficiency Virus

Because a retrospective study detected 13 negative Western blots out of 38 single-use diagnostic system (SUDS)-positive cases over a 1-year period, we performed a prospective study to compare the performance of the SUDS test with that of enzyme immunoassay (EIA). Of 888 SUDS-tested sera, 875 (98.4%) were both SUDS and EIA negative and 5 (0.6%) were SUDS, EIA, and Western blot positive. The rate of SUDS-positive samples decreased from 3.16/month in the retrospective study to 1.33/month in the prospective study. The immunoas-says had sensitivities and specificities of 100 and 99.7 (SUDS) and 100 and 99.4 % (traditional EIA), respec-tively. In laboratories with experienced personnel, the SUDS test performs as well as the EIA as a screen for infection with the human immunodeficiency virus. Occasionally, the human immunodeficiency virus (HIV) sta-tus of an individual is needed urgently. For example, a rapid HIV status result may be needed for initiating prophylactic therapy after possible HIV exposure (1), prior to listing pa-tients for organ transplantation (4, 6), and in a public health setting (3). The Food and Drug Administration-approved Murex Single-Use Diagnostic System (SUDS; Abbott Labora