Field evaluation of Standard Diagnostics' Bioline HIV/Syphilis Duo test among female sex workers in Johannesburg, South Africa
BACKGROUND:
Point-of-care
tests provide immediate results with the opportunity for same-day interventions
with improved public health outcomes. A dual HIV/syphilis test enables early
treatment of both diseases.
METHODS:
We
conducted a field evaluation of the Standard Diagnostics' SD Bioline
HIV/Syphilis Duo test (SD Bioline) among female sex workers. SD Bioline was
conducted on finger-prick blood according to manufacturer's instructions and
compared with (i) Genscreen HIV1/2 (third generation) and Vironostika Ag/Ab
(fourth generation) assays for HIV, and (ii) Treponema pallidum particle
agglutination (TPPA) and rapid plasma reagin (RPR) assays for syphilis. A
negative TPPA test was considered negative, a TPPA-confirmed RPR titre ≤1:4 as
past infection and a TPPA-confirmed RPR titre ≥1:8 as active syphilis.
Sensitivity, specificity, positive and negative predictive values were
calculated.
RESULTS:
Of 263
women recruited, 14 (5.3%) declined an HIV test. Among the remaining 249 women,
187 (75.1%) were HIV positive, 51 (20.5%) had syphilis antibodies with seven
(2.8%) active infections. For HIV, the sensitivity and specificity were 98.9%
(95% CI 95.8% to 99.8%) and 100% (95% CI 92.7% to 100%). For syphilis, the
sensitivity and specificity were 66.7% (95% CI 52.0% to 78.9%) and 98.0% (95%
CI 94.5% to 99.3%). Sera with high TPPA titres were more likely to test
positive.
CONCLUSIONS:
In
field conditions, while the SD Bioline test has high sensitivity and
specificity for HIV and high specificity for syphilis, the test has lower
sensitivity for syphilis than reported from laboratory evaluations. As the dual
test detects only two thirds of syphilis cases, it should only be used in areas
with weak screening programmes.
- 1Faculty of Health Sciences, Wits Reproductive Health and HIV Institute, University of the Witwatersrand, Johannesburg, South Africa Clinical Microbiology and Infectious Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
- 2Faculty of Health Sciences, Wits Reproductive Health and HIV Institute, University of the Witwatersrand, Johannesburg, South Africa.
- 3Centre for HIV and STIs, National Institute for Communicable Diseases, Johannesburg, South Africa.
- 4Centre for HIV and STIs, National Institute for Communicable Diseases, Johannesburg, South Africa Western Sydney Sexual Health Centre, Western Sydney Local Health District, Parramatta, Australia.
- Sex Transm Infect. 2016 May 6. pii: sextrans-2015-052474. doi: 10.1136/sextrans-2015-052474.
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