Usefulness of rapid diagnostic test in the diagnosis of asymptomatic malaria in HIV infected children on cotrimoxazole prophylaxis in Benin City, Nigeria

Abstract

Background: Rapid diagnostic test (mRDT) is a useful tool in demonstrating parasitologically proven malaria. Its efficacy is however hampered  when parasite density is low. Prophylactic use of cotrimoxazoleas in cases of HIV infected children can cause reduction in parasite count. It is  doubtful if mRDT will retain its diagnostic usefulness among such individuals.
Objectives: The study sought to evaluate the diagnostic value of mRDT in HIV infected children on cotrimoxazole prophylaxis in Benin City.
Methods: In the prospective, cross sectional and descriptive study, we assessed malaria parasitaemia using standard methods in microscopy and parasite density and malaria antigenaemia using Care Start Pf (monoclonal antibodies specific to histidine rich protein – 2 antigen) in 221 each of HIV infected subjects on cotrimoxazole managed in a specialist clinic and HIV negative controls all seen at the University of Benin Teaching Hospital between April and June 2016.
Results: Malaria antigenaemia rate MAr (20.8%) was lower than malaria parasitaemia rate MPr (24.4%) in subjects. MAr (20.8) and MPr (24.4%) in  subjects were higher than MAr (18.10%) and MPr (17.7%) in controls. Mean (SEM) parasite count in subjects of was low (50.88 + 2.24 per μl). Using microscopy as gold standard the sensitivity, specificity, PPV and NPV of mRDT in subjects were 77.8%, 97.6%, 91.3% and 93.1%. Corresponding values in controls were 100.0%, 99.5%, 97.5% and 100.0%.Youden indices for subjects and controls were 0.75 and 0.99.
Conclusions/Recommendations: Sensitivity of mRDT in HIV infected children on cotrimoxazole prophylaxis for opportunistic infections (OI) is reduced. However the indices of specificity, PPV and NPV are high enough to retain its value in the evaluation of HIV infected children for  asymptomatic malaria and perhaps the clinical disease.

Keywords: mRDT, Utility, HIVinfected Children, Cotrimoxazoleprophylaxis, Benin City