Comparative Diagnosis of Plasmodium Falciparum Malaria with a Histidine-Rich Protein 2 Rapid Diagnostic Test and Light Microscopy in a Hospital Setting in Katsina-Ala Nigeria
Malaria diagnosis with the rapid diagnostic tests (RDTs) is recommended for malaria endemic countries. However, some brands of the malaria RDTs currently in circulation may not satisfy the minimum requirement for diagnosis and clinical management of falciparum malaria. This study compared the performance of a histidine-rich protein 2 CareStartTM (Pf) malaria RDT, with light microscopy in the diagnosis of Plasmodium falciparum in a hospital setting in Katsina-Ala, Nigeria. A total of 723 hospital patients; 411 symptomatic and 312 asymptomatic were screened with CareStartTM (Pf) malaria RDT and light microscopy for the diagnosis of P. falciparum malaria. Using light microscopy as the reference test, the results indicated that the prevalence of P. falciparum was 25.9% by CareStart RDT and 23.2% by light microscopy. The level of the two tests concordance was outstanding in symptomatic malaria: kappa (k) = 0.92 (95% CI = 0.87 – 0.96) p < 0.001, and substantial in asymptomatic malaria: k = 0.70 (95% CI = 0.60 – 0.79) p < 0.001. Sensitivity = 86.8%; 95.7%, while specificity = 91.5%; 97.0% in asymptomatic and symptomatic malaria respectively. Similarly, positive predictive value = 67.6%; 92.4%, while negative predictive value = 97.1% and 98.3% in the same group of patients. These results suggest that CareStartTM (Pf) malaria RDT is suitable for the diagnosis of P. falciparum malaria. However, it has a tendency to overestimate malaria prevalence, albeit having a reduced probability of detecting truly positive P. falciparum infections in a hospital setting.
Keywords: malaria diagnosis, microscopy, rapid diagnostic test, histidine-rich protein 2