title: Comparison of two culture approaches, blind passage and dual observation, for detecting Chlamydia trachomatis in various prevalence populations.
abstract: Chlamydia trachomatis diagnosis in our laboratory consisted of dual inoculation of shell vials and detection of inclusions by using fluorescein-conjugated monoclonal antiserum; the second culture vial was conventionally used for blind passage when the first vial was negative. We compared the increase in positivity using blind passage with that of a strategy utilizing observation of two stained monolayers (dual observation) without blind passage, in an effort to reduce the reporting time and labor associated with the conventional approach. A total of 4,329 specimens were obtained from an obstetrics and gynecology (OB-GYN) clinic (2,563 specimens) and the sexually transmitted disease clinic (1,766 specimens). These specimens were used to compare the two strategies. Blind passage of 1,269 initially culture-negative specimens from the OB-GYN clinic resulted in an additional 6 positive chlamydial diagnoses. In comparison, a similar number of specimens (1,294) from the OB-GYN clinic collected subsequently to the first group were tested by dual observation. There were five additional positive findings. A similar evaluation of specimens from the sexually transmitted disease clinic was performed. Blind passage of 313 initially culture-negative specimens yielded 3 additional positive diagnoses, whereas dual observation of 1,435 similar specimens resulted in 9 positive diagnoses. On the basis of analysis of 4,332 specimens, sensitivity of dual observation is comparable to that of blind passage; labor, cost, and reporting time of dual observation are reduced in comparison to those of blind passage.
authors.affiliation: Division of Clinical Microbiology and Immunology, Erie County Medical Center, Buffalo, New York 14215.
authors.forename: S J
authors.initials: SJ
authors.lastname: Zimmerman
authors.forename: E
authors.initials: E
authors.lastname: Moses
authors.forename: N
authors.initials: N
authors.lastname: Sofat
authors.forename: W R
authors.initials: WR
authors.lastname: Bartholomew
authors.forename: D
authors.initials: D
authors.lastname: Amsterdam
mesh_terms: D001431:Bacteriological Techniques / Q000191:economics / Q000706:statistics & numerical data; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000453:epidemiology; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D003365:Costs and Cost Analysis; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D012680:Sensitivity and Specificity; D015231:Sexually Transmitted Diseases, Bacterial / Q000175:diagnosis* / Q000453:epidemiology; D014481:United States / Q000453:epidemiology