INFLUENCE OF ENDOCERVICAL SPECIMEN ADEQUACY ON PCR AND DIRECT FLUORESCENT-ANTIBODY STAINING FOR DETECTION OF CHLAMYDIA-TRACHOMATIS INFECTIONS

The cellular quality of the endocervical swab specimen used for the de tection of Chlamydia trachomatis may dramatically impact the sensitivi ty of the diagnostic assay used, An evaluation of the adequacy of 319 endocervical swab specimens from women attending two inner-city sexual ly transmitted disease and family planning clinics, as well as five hi gh school-based family planning clinics, was performed, and the result ing data were compared with the diagnostic results obtained by both Am plicor PCR and Microtrak direct fluorescent-antibody (DFA) staining. T he swab from each patient was rolled across the open circular area of a DFA slide and then used to inoculate a transport tube for PCR (Roche ), after which the swab was discarded, The slides were stained and exa mined by epifluorescence microscopy for the presence of C., trachomati s elementary bodies and for the presence and number of cell types to d etermine specimen adequacy. Cellular adequacy for a cervical swab spec imen was defined as the presence of one or more columnar epithelial or metaplastic epithelial cells or the presence of more than 100 erythro cytes per high-power microscopic field. Of the 319 specimens read by D FA, 204 (63.9%) were determined to be adequate. There were 34 (10.7%) positive specimens by DFA and/or PCR. Twenty-nine (9.1%) specimens wer e positive by PCR, 20 (6.3%) specimens were DFA positive, and 15 (4.7% ) were concordantly positive by both tests, The prevalence of chlamydi a among adequate specimens was 14.2% (29/204), compared to 4.3% (5/115 ) for inadequate specimens (P < 0.0001), Variations in specimen qualit y and the sensitivity of the diagnostic assay used have a significant impact on determining the prevalence of C. trachomatis in a population .