Field evaluation of simple rapid tests in the diagnosis of syphilis

The aim of this study was to detect the sensitivity and specificity of rapid syphilis diagnostic tests (immunochromatographic strip [ICS] test and rapid test device [RTD]) performed by low-skilled paramedics in field clinics and by highly-skilled technologists in laboratories and compare them with the gold standard (rapid plasma reagin [RPR] and Treponema pallidum haemagglutination [TPHA]) tests for diagnosis of syphilis. A cross-sectional study was conducted among female sex workers (FSWs) in Dhaka, Bangladesh, from August 2004 to July 2005. Blood specimens were tested for syphilis using (i) ICS, (ii) RTD, (iii) RPR tests performed by low-skilled paramedics; and (i) ICS, (ii) RTD, (iii) RPR and (iv) TPHA tests by highly-skilled technologists. The sensitivity and specificity of the ICS and RTD test performed by low- and highly-skilled personnel were compared with the gold standard. A total of 684 FSWs were enrolled and the prevalence of syphilis among FSWs was 20.8% as determined by the gold standard. There was no significant difference in the performance of ICS test done by paramedics in the field when compared with the gold standard performed by highly-skilled technologists in the laboratory (sensitivity, 94.45%; specificity, 92.6%). The ICS test could fulfil the need for a non-invasive, rapid screening test for syphilis.