As presented at the 99th General Meeting of the American Society for Microbiology, May 1999. Multicenter Evaluation of the BDProbeTec ™ ET System in Detecting Chlamydia trachomatis and Neisseria gonorrhoeae from Endocervical and Urine Specimens in Women D.V. FERRERO 1 *, L. BUCK-BARRINGTON 2 , H. MEYERS 2 , G.S. HALL 3 , M. TUOHY 3 , D. WILSON 3 1 Disease Control & Prevention Division, San Joaquin Co. Public Health Services, Stockton, CA, USA, 2 Regional Public Health Laboratory, San Joaquin Co. Public Health Services, Stockton, CA, USA, 3 Clinical Laboratory, Cleveland Clinic Foundation, Cleveland, OH, USA INTRODUCTION The most prevalent sexually transmitted disease in the United States today is caused by Chlamydia trachomatis and the number of reported cases continues to rise. (1) During 1998 the nation has experienced the first increase in the number of reported cases of gonorrhea following a several year decline in reported cases. The significance of serious complications related to chlamydia and gonorrhea infections has been well established. (2) Urethritis, epididymitis, proctitis, cervicitis, pelvic inflammatory disease, infant pneumonia, and conjunctivitis are some of the potential outcomes of infection with these diseases. The advent of managed care and shrink- ing public health budgets have made rapid early accurate diagnosis and adequate treatment even more critical. The capability of testing using non- invasive specimens such as urine and the ability to acquire specimens in non-traditional venues has been reported as an important intervention effort. (3, 4) Traditional cell culture methods have been the gold standard for diag- nosis of chlamydia infections. However, cell culture methods are expen- sive, time consuming and subject to lab-to-lab variation. The introduction of enzyme immunoassay (EIA) tests and the DNA probe test (Gen-Probe, Inc.) for direct detection of antigen in patient samples provided an alter- native to tissue culture. (5) The sensitivity and specificity of EIA and DNA probe tests are comparable to culture. Recently, nucleic acid amplification methods based on the polymerase chain reaction (PCR), ligase chain reac- tion (LCR) and transcription mediated amplification (TMA) assays have been reported to offer improved performance over culture and other non- culture methods. (6, 7, 8) These tests have expanded the capability for obtain- ing non invasive specimens in non-traditional settings. The latest amplified procedure to be evaluated in the United States is the Becton Dickinson BDProbeTec™ ET (BDPT) assay. (9) The BDPT assay utilizes strand displacement amplification (SDA) to simultaneously amplify and detect Chlamydia trachomatis and Neisseria gonorrhoeae deoxyribonucleic acid (DNA) in male urethral swab and urine specimens and female endocervical and urine specimens. The purpose of this study was to assess the performance characteristics of the BDPT assay with female endocervical swab and first catch urine (FCU) specimens in a low prevalence population. The BDPT assay perfor- mance was compared to a gold standard, which compared BDPT to stan- dard culture methods and DFA for CT and culture for GC. The BDPT assay performance was further compared to an “enhanced” gold standard defined as a laboratory diagnosis of infection based upon the combined criteria of culture, direct fluorescent antibody testing of the spun down portion of the CT transport media, GC culture confirmation, and another nucleic acid amplification test (LCR). METHODS Four endocervical swabs and a urine specimen were collected from each female patient seen in family planning clinics or OB/GYN clinics. The swab order of collection was randomized. One swab sample was used for the cul- ture of C. trachomatis, one swab sample was used for the culture of N. gon- orrhoeae, one swab sample was tested by the BDPT assay and the fourth ABSTRACT (Revised) ■ The performance of the BDProbeTec™ ET System (BDPT) for the detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) was evaluated. BDPT uses thermophilic Strand Displacement Amplification (SDA) technology to simultaneously ampli- fy and detect target DNA. Endocervical swab and first catch urine (FCU) speci- mens were obtained from 562 female patients attending family planning clinics. BDPT performance was com- pared to culture and an “enhanced” gold standard based upon the combined criteria of culture, direct fluorescent antibody testing, and another nucleic acid amplification test (LCR). The prevalence of CT was 5.0% and for GC, 1.5%. The sensitivity of the CT assay compared to the “enhanced” gold standard for endocervical swab speci- mens was 96.4% (27/28), with a specificity of 98.5% (515/523); and for FCU specimens the sensitivity was 100.0% (26/26), with a specificity of 98.2% (427/435). The sensitivity of the GC assay compared to the “enhanced” gold standard for endocervical swab speci- mens was 100% (8/8), with a specificity of 99.4% (536/539); and for FCU specimens the sensitivity was 83.3% (5/6), with a specificity of 99.3% (441/444). CT culture sensitivity was 64.3% (18/28) and for GC cul- ture, 87.5% (7/8). The BDProbeTec™ ET System is a highly sensitive and specific DNA amplification assay.