Detection of Chlamydia trachomatis in symptomatic and asymptomatic populations with urogenital specimens by AMP CT (Gen-Probe Incorporated) compared to others commercially available amplification assays

The present study was designed to evaluate the sensitivity and specificity of AMP CT (Gen-Probe Incorporated, San Diego, CA, USA) on urogenital specim ens taken from symptomatic patients and on first void urine (FVU) specimens from asymptomatic patients. In symptomatic patients, 618 specimens from 14 0 men (140 urethral swabs and 140 FVU) and 202 women (202 endocervical swab s and 136 FVU) were tested by using cell culture, AMP CT and Amplicor Chlam ydia trachomatis MWP(TM) (microwell plate) (Roche Diagnostics, Somerville, NJ, USA) on genital samples, and AMP CT and Amplicor on FVU. A clinical spe cimen was considered to be truly positive if either the cell culture was po sitive and/or both AMP CT and Amplicor were positive. In the asymptomatic p opulation, a total of 300 FVU (136 women and 164 men) were tested by four a mplification methods, AMP CT, LCX(TM) (Abbott, Abbott Park, IL, USA), Ampli cor MWP, and Cobas Amplicor. A subject was considered to be infected when t wo or more amplification methods were positive. In the symptomatic populati on (prevalence 13%), concordant results were observed in 320/342 cases (93. 5%). After analysis of discordant results, the sensitivity of AMP CT, Ampli cor, and culture was 100%, 95.5%, 68.8%7 respectively, and the specificity was 98.3%, 99.3%, 100% respectively. The number of false negative results b y AMP CT in urine, probably due to labile inhibitors, was 3/276 (1%). In th e asymptomatic population, the results were concordant in 298/390 (99.3%), seven positive and 291 negative. Two results were considered false positive s, one by Cobas Amplicor, one by AMP CT. Compared to other amplification me thods, AMP CT is at least as sensitive for the identification of chlamydial infection in symptomatic and asymptomatic men and women on genital or urin e specimens. (C) 2000 Elsevier Science Inc. All rights reserved.