CAPTURE-S, A NONTREPONEMAL SOLID-PHASE ERYTHROCYTE ADHERENCE ASSAY FOR SEROLOGICAL DETECTION OF SYPHILIS

A solid-phase erythrocyte adherence assay has been developed for the s erological detection of reagin antibodies in syphilis, Capture-S (Immu cor, Inc., Norcross, Ga.) is a nontreponemal, qualitative screening te st for the detection of immunoglobulin G (IgG) and IgM antilipid antib odies in serum or plasma samples from blood donors, The Capture-S assa y utilizes a modified Venereal Disease Research Laboratory antigen bou nd to microtitration wells and anti-IgG- plus anti-IgM-coated indicato r erythrocytes as the detection system, The Capture-S assay was evalua ted at six separate sites on 10,942 specimens, For patient samples of clinically diagnosed syphilis categories (n = 366), the Capture-S assa y yielded a sensitivity of 80.7% versus 80.3% for the rapid plasma rea gin (RPR) card test (Becton Dickinson Microbiology Systems, Cockeysvil le, Md,), In comparative experiments on patient and donor samples (n = 10,222), the Capture-S assay demonstrated a sensitivity of 94% compar ed to 91.2% for the RPR card test, The Capture-S and RPR card tests pr oduced essentially equivalent specificities of 99.2% and 99.3%, respec tively, for this sample population, For five test sites, the Capture-S and RPR card test demonstrated a 98.3% agreement (10,085 of 10,264) o f test results. These evaluations indicate that the Capture-S compares favorably to the RPR card test in assay sensitivity and specificity, with the added benefits of ease of use, accommodation of high-volume t esting, and potential for automation.