Assessment of enzyme immunoassay and immunofluorescence tests for detection of Chlamydia trachomatis

Abstract

Two rapid diagnostic tests for Chlamydia trachomatis (Microtrak, Syva Co., Palo Alto, Calif.; and Chlamydiazyme, Abbott Laboratories, North Chicago, 111.) were evaluated in comparison with growth of the organism in tissue culture for 2,030 urogenital specimens from men and women. Neither test performed as well as culture, which detected 296 of 310 positive specimens. The overall sensitivity and specificity for Microtrak were 73 and 99%; corresponding values for Chlamydiazyme were 83 and 98%. The majority of false-negative results with both rapid tests occurred when cultures contained less than 10 inclusions per cover slip. There were also areas of unconfirmed reactivity for both tests that led us to suggest that a reporting category of "suspicious" be developed for certain test results. For Microtrak, the suspicious result is a slide containing fewer than 10 elementary bodies; for Chlamydiazyme, it is any absorbance reading less than 0.4. Creation of a "suspicious" category would lower the sensitivity for Chlamydiazyme considerably, to 64%, and increase the positive predictive value for females to 95%. Although this may result in the underreading of some specimens from males, the tests could then be used with greater confidence in females for whom testing is essential for appropriate treatment.

Effect of endocervical specimen quality on detection of Chlamydia trachomatis and on the incidence of false-positive results with the Chlamydiazyme method

“…E-M cells were found in as many as 82 to 100% of the specimens obtained by some of these individuals. In previous evaluations of endocervical swab samples submitted for direct fluorescentantibody detection of C. trachomatis, from 4 to 45% of the specimens have been found to be inadequate (5,16,22,27,29,33,37).…”

Diagnosis of Avian Chlamydiosis: Specificity of the Modified Giménez Staining on Smears and Comparison of the Sensitivity of Isolation in Eggs and Three Different Cell Cultures

“…Thirty-two birds were positive by direct identification, while D I F following isolation was only positive in 29 birds. Both false-positive results using DIF on smears and falsenegative results in isolation attempts have been described (Err et al, 1986;HIPP et al, 1987;TIMMS et al, 1988;MOHAN, 1989). False-positive results using DIF on smears could be due to nonspecific immunoglobulin binding or to cross-reactivity of the antibodies with other micro-organisms.…”

Nachweis von Chlamydia psittaci in Vaginalausfluß von Rindern: Eine notwendige Erweiterung der bakteriologischen Diagnostik zur ätiologischen Klärung von Fruchtbarkeitsstörungen beim weiblichen Rind

“…Voraussetzung fur die Verknupfung der beiden Bedingungen war, den 'cut-off' des ELISA anhand der OD der prainkubierten Proben nach der oben aufgefuhrten Formel zu berechnen (TIJSSEN, 1985). (HIPP et al, 1987;KELLOGG et al, 1990;MARDH et al, 1990;MONCADA et al, 1990;MILLS et al, 1992;OLSEN und SAMBOL, 1993;WARREN et al, 1993) (MILLS et al, 1992).…”