Comparison of two commercial assays and microscopy with PCR for diagnosis of malaria

Abstract

This study compared conventional PCR with microscopy and 2 rapid detection methods, the pLDH which detected lactic dehydrogenase enzyme produced by actively metabolizing organisms and the malaria antibody tests. The sensitivity of PCR was 1 parasite/microl, i.e.: 50 times more sensitive than microscopy. When PCR was compared with microscopy, the sensitivity and specificity were 90% & 100% respectively. The sensitivity recorded was pLDH test in comparison to PCR (95%). The malaria antibody test recorded the least sensitivity (68%) PCR proved as the gold standard for evaluation of applied tests and the newly introduced ones. In absence of an expert microscopist, the pLDH test could substitute for microscopy. The test proved valuable to assess clinical cure, and predict drug resistance. Its advantage over microscopy was the ability to diagnose infection with low parasitemic patients. Antibody rapid tests might be not valuable in acute cases, but still accepted as a tool in epidemiological studies and in screening patients in blood banks in malaria endemic areas.