EVALUATION OF THE BIOSTAR CHLAMYDIA OIA ASSAY WITH SPECIMENS FROM WOMEN ATTENDING A SEXUALLY-TRANSMITTED DISEASE CLINIC

Chlamydia trachomatis infections are the most prevalent sexually trans mitted diseases (STDs) in the United States. In acute-care settings su ch as clinics and emergency rooms, a desirable chlamydia screening ass ay should exhibit good sensitivity and good specificity and should pro vide test results while the patient is still present. The Biostar Chla mydia OIA (Biostar, Inc., Boulder, Cole.) is an optical immunoassay (O IA) that provides test results in less than 30 min and that uses a tes t format that allows office-based testing, This assay is performed ent irely at room temperature without the need for rotators or other speci alized equipment, The goal of this study was to compare the performanc e of the Biostar Chlamydia OIA for the detection of C. trachomatis wit h the performance of cell culture, direct fluorescent-antibody (DFA) a ssay (Syva MicroTrak; Syva Co., Pale Alto, Calif,), and PCR (Roche Amp licor Chlamydia trachomatis; Roche, Branchburg, N.J,) for the detectio n of C, trachomatis infections in women attending an urban STD clinic. For calculations of relative test performance (sensitivity, specifici ty, and positive and negative predictive values), patient specimens th at yielded positive results by two or more of the four assays (cell cu lture, DFA assay, PCR, and OIA) were classified as ''true infections.' ' By these criteria, 42 of 306 total specimens were classified as posi tive for C. trachomatis (positive prevalence, 13.7%), 11 (3.6%; 10 by PCR and 1 by DFA assay) were positive by a single assay, and 253 (82.7 %) were negative by all four tests. All culture-positive specimens wer e also positive by at least one other assay, Among the culture-negativ e specimens, 14 (5%) specimens were positive by two of the three non-c ulture-based assays used. By using the criterion that positivity by at least two of the tests indicated a true infection, the relative sensi tivities were as follows: culture and PCR, 92.9% each; Biostar Chlamyd ia OIA, 73.8%; and DFA assay, 59.5%.