Original articles

False-positive HIV DNA PCR testing of infants: Implications in a changing epidemic

Ute Dagmar Feucht, Brian Forsyth, Mariana Kruger

Abstract


Aim. To examine false-positive HIV DNA polymerase chain reaction (PCR) test results in children, and the potential implications for the paediatric HIV epidemic in sub-Saharan Africa.
Methods. A review was done of records over a 6-year period of children less than 18 months old at an HIV treatment site in South Africa, to evaluate those with an initial ‘false’-positive HIV DNA PCR result, but later proven to be HIV-uninfected with HIV DNA PCR and/or quantitative HIV RNA PCR tests. We calculated the influence of changing HIV transmission rates on predictive values (PV) of HIV DNA PCR tests in a hypothetical population of all HIV-exposed infants over a 1-year period. (Positive PV: proportion of individuals with a positive test with disease; negative PV: proportion of individuals with negative test and no disease).
Results. Of 718 children, 40 with an initial positive HIV DNA PCR test were subsequently proven to be HIV-uninfected, resulting in a positive PV of 94.4%. Most (75%) uninfected children had PMTCT interventions and were asymptomatic or mildly symptomatic (77.5%). Calculations using a test specificity of 99.4%, as reported previously, show a decrease in positive PV using a single-test strategy from 98.6% at 30% HIV transmission rate, to 94.8% at 10% transmission, to 62.5% at 1% transmission. Reduction in test specificity further decreases positive PV at low transmission rates.
Conclusion. Decreasing mother-to-child HIV transmission rates reduce the positive predictive value of a single HIV DNA PCR test result, necessitating adaptations to diagnostic algorithms to avoid misdiagnosis and inappropriate treatment, especially with early initiation of antiretroviral therapy in asymptomatic infants.

Authors' affiliations

Ute Dagmar Feucht, Department of Paediatrics, Kalafong Hospital, University of Pretoria, South Africa

Brian Forsyth, Department of Pediatrics, Yale University, New Haven, CT, USA

Mariana Kruger, Department of Paediatrics and Child Health, University of Stellenbosch, South Africa

Full Text

PDF (229KB) HTML

Keywords

HIV; vertical transmission; infant diagnosis; polymerase chain reaction; false-positive

Cite this article

South African Medical Journal 2012;102(3):149-152.

Article History

Date submitted: 2011-04-14
Date published: 2012-02-23

Article Views

Abstract views: 2430
Full text views: 8985

Comments on this article

*Read our policy for posting comments here