Clinic-based evaluation of Clearview Chlamydia MF for detection of Chlamydia trachomatis in vaginal and cervical specimens from women at high risk in China
- Y-P Yin1,
- R W Peeling2,
- X-S Chen1,
- K-L Gong1,
- H Zhou3,
- W-M Gu4,
- H-P Zheng5,
- Z-S Wang6,
- G Yong7,
- W-L Cao8,
- M-Q Shi1,
- W-H Wei1,
- X-Q Dai1,
- X Gao1,
- Q Chen1,
- D Mabey9
- 1National Center for STD Control, Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Dermatology, Nanjing, China
- 2World Health Organization, Geneva, Switzerland
- 3Shenzhen Institute of Dermatology, Shenzhen, China
- 4Shanghai Hospital for Dermatology and STDs, Shanghai, China
- 5Guangdong Institute of Dermatology and Venereology, Guangzhou, China
- 6Fujian Institute of Dermatology and Venereology, Fuzhou, China
- 7Sichuan Institute of Dermatology and Venereology, Chengdu, China
- 8Guangzhou Institute of Dermatology and Venereology, Guangzhou, China
- 9London School of Hygiene & Tropical Medicine, London, UK
- Correspondence to: Dr Yue-Ping Yin National Center for STD Control, 12 Jiangwangmiao Street, Nanjing 210042, China; ypyinc{at}vip.163.com
- Accepted 6 November 2006
- Published Online First 22 November 2006
Abstract
Objectives: To determine the performance of a rapid Chlamydia trachomatis (CT) test (Clearview Chlamydia MF) compared to the current “gold standard” (Roche Amplicor CT assay) test, and to assess acceptability of the tests to patients.
Methods: A total of 1497 women at sexually transmitted diseases (STD) clinics or re-education centres in six urban cities (Shanghai, Nanjing, Shenzhen, Guangzhou, Chengdu and Fuzhou) in China participated in the study. Three vaginal and three cervical swabs were collected from each participant. Rapid CT tests were performed locally on the first vaginal and cervical swabs and the results were read independently by two staff members. The second and third swabs were randomised for performing the Roche CT assay at the National STD Reference Laboratory. Acceptability of the rapid tests to patients was determined by asking patients in clinics about their willingness to wait for the results.
Results: The prevalence of CT was 13.2% (197/1497), as determined by the Roche assay with cervical specimens. CT was detected in 78 vaginal and 127 cervical specimens by the rapid test and the positive rates determined with cervical specimens were significantly higher than those with vaginal specimens (p<0.001). There was good agreement between the results read by two independent staff for either vaginal or cervical specimens (both κ = 0.98, p<0.001). Sensitivities for vaginal and cervical specimens were 32.8% and 49.7%, respectively, and specificities were 99.2% and 97.9%, respectively. The positive predictive value was 85.7% for vaginal and 78.4% for cervical specimens. The vast majority of the patients (99.1%) were willing to wait up to two hours for the results.
Conclusion: Clearview Chlamydia MF, while yielding a rapid result and requiring minimal laboratory facilities, had unacceptably low sensitivity compared to a nucleic acid amplification test. Rapid tests yielding results within one hour are generally accepted by the clients.
- FRCs, female re-education centres
- NAAT, nucleic acid amplification test
- NGU, non-gonococcal urethritis
- NPV, negative predictive value
- PCR, polymerase chain reaction
- PID, pelvic inflammatory disease
- PPV, positive predictive value
- SEVs, sex entertainment venues
- STD, sexually transmitted disease
- STDCs, STD clinics
- WHO, World Health Organization
Footnotes
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Conflict of interest statement: Clearview Chlamydia MF test kits were provided by Unipath Ltd in the UK via the WHO/TDR Programme on Sexually Transmitted Diseases Diagnostics Initiative (SDI)
