Improving the coverage and accuracy of syphilis testing: The development of a novel rapid, point-of-care test for confirmatory testing of active syphilis infection and its early evaluation in China and South Africa (original) (raw)
Related papers
Prospective, multi-centre clinic-based evaluation of four rapid diagnostic tests for syphilis
Sexually Transmitted Infections, 2006
Objectives: To evaluate prospectively four rapid, point-of-care serological tests for syphilis in prenatal or high risk populations in four countries. Methods: Tests were performed on consecutive clinic attenders, using whole blood in the clinic, and whole blood and serum in the laboratory. The sensitivity and specificity of each test was evaluated, using a standard treponemal test (Treponema pallidum haemagglutination assay (TPHA) or fluorescent treponemal antibody, absorbed (FTA-ABS) as gold standard. Non-treponemal tests (rapid plasma reagin (RPR) or venereal diseases research laboratory (VDRL) tests) were also performed on all subjects at three sites. Results: The specificity of each rapid test was .95% at each site. Sensitivities varied from 64-100% and, in most cases, were lower when whole blood was used rather than serum. Conclusions: Rapid serological tests for syphilis are an acceptable alternative to conventional laboratory tests. Since they do not require equipment or electricity, they could increase coverage of syphilis screening, and enable treatment to be given at the first clinic visit.
Accelerating worldwide syphilis screening through rapid testing: a systematic review
The Lancet Infectious Diseases, 2010
Syphilis is a persistent public health issue in many low-income countries that have limited capacity for testing, which traditionally relies on a sensitive non-treponemal test and then a specifi c treponemal test. However, the development of a new rapid treponemal test provides an opportunity to scale up syphilis screening in many settings where traditional tests are unavailable. This systematic review of immuno chromatographic strip (ICS) syphilis tests describes the sensitivity and specifi city in two important clinical settings: sexually transmitted infection (STI) clinics and antenatal clinics. Clinical data from more than 22 000 whole blood, plasma, or fi ngerstick ICS tests obtained at STI or antenatal clinics were retrieved from 15 studies. ICS syphilis tests have a high sensitivity (median 0·86, interquartile range 0·75-0·94) and a higher specifi city (0·99, 0·98-0·99), both comparable with non-treponemal screening test characteristics. Further research evaluating ICS syphilis tests among primary syphilis cases and among patients infected with HIV will be essential for the eff ective roll-out of syphilis screening programmes.
The Trade-Off between Accuracy and Accessibility of Syphilis Screening Assays
PLoS ONE, 2013
The availability of rapid and sensitive methods to diagnose syphilis facilitates screening of pregnant women, which is one of the most cost-effective health interventions available. We have evaluated two screening methods in Tanzania: an enzyme immunoassay (EIA), and a point-of-care test (POCT). We evaluated the performance of each test against the Treponema pallidum particle agglutination assay (TPPA) as the reference method, and the accessibility of testing in a rural district of Tanzania. The POCT was performed in the clinic on whole blood, while the other assays were performed on plasma in the laboratory. Samples were also tested by the rapid plasma Reagin (RPR) test. With TPPA as reference assay, the sensitivity and specificity of EIA were 95.3% and 97.8%, and of the POCT were 59.6% and 99.4% respectively. The sensitivity of the POCT and EIA for active syphilis cases (TPPA positive and RPR titer ≥1/8) were 82% and 100% respectively. Only 15% of antenatal clinic attenders in this district visited a health facility with a laboratory capable of performing the EIA. Although it is less sensitive than EIA, its greater accessibility, and the fact that treatment can be given on the same day, means that the use of POCT would result in a higher proportion of women with syphilis receiving treatment than with the EIA in this district of Tanzania.
An Unexpected Result in an Evaluation of a Serological Test to Detect Syphilis
Pathology, 1999
Traditional tests for detection of syphilis are labour intensive and costly. Enzyme immunoassays (EIAs) are readily automated and cost effective if large numbers of tests are performed. Four experiments were devised to evaluate a syphilis EIA test kit where resources are limited: (1) testing antenatal patients; (2) testing refugees; (3) testing a high prevalence population; and (4) testing "problem sera" (containing autoantibodies or antibodies to other infective agents). Forty-one available syphilitic sera from antenatal patients were tested to evaluate sensitivity. Specificity was determined through testing sera determined to be nonreactive with rapid plasma reagin and Treponema pallidum hemagglutination tests, calculating the sample size (456) on the confidence interval (CI) required. Two runs were performed on antenatal sera, giving sensitivities of 32% (95% CI: 20%,47%) and 37% (95% CI: 24%, 52%) and specificities of 92% (95% CI: 89%, 94%) and 90% (95% CI 87%, 92%), respectively. We present a method to evaluate a serological test where resources are limited. Unexpectedly, the test kit performed poorly as a screening test. New serological tests need to be evaluated in-house prior to adoption.
Journal of Immunological Methods, 2018
Background Serological methods have great importance for the detection of Treponema pallidum antibodies in syphilis diagnosis. The goal of the present study is to evaluate various commercially available screening assays in comparison with the FTA-abs test. Methods A total of 363 serum samples were enrolled in the study. Following routine testing including RPR and TPHA tests, each sample was tested by treponemal immunoassays (Chorus Syphilis Screen Recombinant, Architect Syphilis TP, Syphilis Virclia Monotest, Siemens Advia Centaur Syphilis, Euroimmun Treponema pallidum Screen ELISA, Vircell Syphilis ELISA IgG+IgM, SD Bioline Syphilis). The result obtained from each test was compared with the confirmatory FTA-abs test. Kappa (κ) coefficients were used to compare the concordance of the tests. Results When the various tests were evaluated in comparison with the FTA-abs test, the sensitivity, specificity and percent agreement of each test were as follows:
Sexually Transmitted Infections, 2011
Background Algorithms for syphilis serologic testing traditionally have relied on screening with a non-treponemal test, such as the rapid plasma reagin (RPR) test or the toluidine red unheated serum test (TRUST) followed by confirmation using a treponemal test, such as Treponema pallidum particle agglutination (TP-PA). To reduce time, material and labour costs, many laboratories, including at the Comprehensive Health Centre in Kingston, Jamaica, have reversed the sequence testing first with a rapid treponemal test followed by non-treponemal testing of reactive sera. Methods In a survey of STIs among men who have sex with men (MSM) in Jamaica, syphilis serologic testing is currently conducted using an initial rapid treponemal SD Bioline Syphilis 3.0 test followed by TRUST for reactive sera. Discordant sera that are Bioline-positive and TRUST-negative, or sera with TRUST titres < or ¼8 undergo supplemental testing by TP-PA. SD Bioline was previously validated in the field and reference laboratory in Jamaica and is 95.2% sensitive and 93.5% specific compared to TP-PA. Here we report the results from sera obtained from 135 MSM in Kingston between December 2010 and February 2011. Results Among 135 sera evaluated using the reverse syphilis screening sequence, 13 (9.6%) had a positive rapid treponemal test. Among these 13 reactive sera, 6 (46.2%) were nonreactive with TRUST. All discordant sera were also reactive by TP-PA, indicating that initial rapid testing did not produce false-positives in this setting. The proportion of discordant syphilis test results was similar among HIV+ and HIV-men. The prevalence of primary syphilis detected by concordant positive treponemal and nontreponemal tests in this survey was 5.2%, compared to 5.3% in a previous survey conducted in this population during 2007e2008 using the traditional screening sequence. Conclusions The prevalence of primary syphilis among MSM in Kingston has not changed since the previous survey. In the current survey using the reverse screening sequence, nearly half of sera that were reactive with the treponemal test produced discordant results with the non-treponemal test. Such results are consistent with previous syphilis infection, treated or untreated, or early primary syphilis in which non-treponemal antibodies have yet to develop. Distinguishing these possibilities requires detailed history and clinical assessment in addition to serologic test results.
Diagnostic accuracy of a point-of-care syphilis test when used among pregnant women in Bolivia
Sexually Transmitted Infections, 2006
Objective: To evaluate the performance of a point-of-care (POC) syphilis test when used in urban Bolivian maternity hospitals. Methods: We tested 8892 pregnant women for syphilis using the Abbott Determine Syphilis TP rapid POC test and rapid plasma reagin (RPR) in the laboratory of four large urban maternity hospitals where national statistics reported a syphilis prevalence of at least 3%. Sera were stored and transferred to the national reference laboratory (INLASA) where RPR testing was repeated. When the reference laboratory staff observed a positive RPR result, a Treponema pallidum particle agglutination assay (TPPA) was performed to confirm these findings. We calculated test performance characteristics for the POC test and hospital RPR using RPR performed at the reference laboratory confirmed by TPPA as the reference standard. Participants received treatment during their initial visit based on the POC test results.
Evaluation of Serological Tests for the Diagnosis of Syphilis
Curēus, 2024
Background Syphilis remains a significant public health concern in India. Ensuring the accuracy of diagnostic tests is crucial for effectively managing this disease. Objectives This study aims to assess the detectability of syphilis using commercially available non-treponemal and treponemal tests due to observed discrepancies in test results, which can lead to confusion and anxiety among healthcare providers and patients. Materials and methods We analyzed 2312 serum samples using the rapid plasma reagin (RPR), Treponema pallidum hemagglutination assay (TPHA), enzyme-linked immunosorbent assay (ELISA), and modified TPHA rapid test, interpreting the results according to the manufacturers' instructions. We evaluated the diagnostic accuracy of all four tests. Concordance between the traditional and reverse algorithms was determined by calculating the percentage of agreement and the kappa (κ) coefficient. Results Of the 2312 samples tested, 34 (1.5%) were positive, and 2098 (90.7%) were negative across all four tests. Comparing the test results with clinical diagnosis, TPHA and TP-ELISA showed the highest sensitivity at 96.08%, while RPR demonstrated the highest specificity at 100%. The agreement between the traditional and reverse algorithms was moderate, with a 97.3% agreement and a κ value of 0.53. Conclusion Reliance on a single serological test for syphilis screening presents limitations. A combined approach using both RPR and TPHA tests can more accurately diagnose and confirm syphilis. This combination strategy is cost-effective and relatively simple to implement.
2021
We evaluate the performance of a point-of-care immunochromatographic test DPP® Syphilis Screen & Confirm Bio-Manguinhos Assay in the whole blood, sera, and plasma of patients with acquired syphilis in. The population was composed by adults stratified in three groups: HIV (N= 174), pregnant women (N= 170) and neither pregnant nor HIV infected (N=149). The results from the dual test were compared to the combination of TPHA+/VDRL≥1:8. The results of sensitivity in people infected with HIV were 100% in whole blood, sera, and plasma, and the specificity ranged from 91.993.1%. The results of sensitivity in pregnant women were 100% in whole blood, sera, and plasma, and the specificity ranged from98.2-99.4%. The results of sensitivity in people neither pregnant nor HIV infected were 80% in whole blood and 100% in sera and plasma. The specificity in whole blood, sera, and plasma, ranged from 96.597.2%. The DPP® Syphilis Screen & Confirm Bio-Manguinhos Assay showed good performance in detecti...
Clinical Infectious Diseases, 2012
Background. Rapid point-of-care (POC) syphilis tests based on simultaneous detection of treponemal and nontreponemal antibodies (dual POC tests) offer the opportunity to increase coverage of syphilis screening and treatment. This study aimed to conduct a multisite performance evaluation of a dual POC syphilis test in China. Methods. Participants were recruited from patients at sexually transmitted infection clinics and high-risk groups in outreach settings in 6 sites in China. Three kinds of specimens (whole blood [WB], fingerprick blood [FB], and blood plasma [BP]) were used for evaluating sensitivity and specificity of the Dual Path Platform (DPP) Syphilis Screen and Confirm test using its treponemal and nontreponemal lines to compare Treponema pallidum particle agglutination (TPPA) assay and toluidine red unheated serum test (TRUST) as reference standards. Results. A total of 3134 specimens (WB 1323, FB 488, and BP 1323) from 1323 individuals were collected. The sensitivities as compared with TPPA were 96.7% for WB, 96.4% for FB, and 94.6% for BP, and the specificities were 99.3%, 99.1%, and 99.6%, respectively. The sensitivities as compared with TRUST were 87.2% for WB, 85.8% for FB, and 88.4% for BP, and the specificities were 94.4%, 96.1%, and 95.0%, respectively. For specimens with a TRUST titer of 1:4 or higher, the sensitivities were 100.0% for WB, 97.8% for FB, and 99.6% for BP. Conclusions. DPP test shows good sensitivity and specificity in detecting treponemal and nontreponemal antibodies in 3 kinds of specimens. It is hoped that this assay can be considered as an alternative in the diagnosis of syphilis, particularly in resource-limited areas.