Evaluation of Microscopy Sensitivity, Specificity in Detection of P. falciparum and P. vivax, Using Monoplex real-time PCR, Gezira, Sudan

Background: Malaria is still account for 200 million cases annually. Microscopy is the gold standard technique for malaria parasites detection. PCR-based techniques can detect malaria infections with high sensitivity. The study aimed to evaluate the sensitivity of microscopy technique in the detection of P. falciparum and P. vivax, using monoplex real-time PCR, Gezira State, Central Sudan. Methods: Microscopic examination for the presence of malaria parasite was performed for 200 Giemsa blood smears. QIAamp DNA Mini Kit Qiagen, Germany, was used for parasite's genomic DNA. Monoplex Real-time PCR was used for the identification and detection of P. falciparum and P. vivax malaria. Results: 71% of samples were positive for P. falciparum by both microscopy and the P. falciparum species-specific real-time PCR and 15% were negative by both. Out of the 40 negative samples by microscopy, 5% were found positive for P. falciparum by P. falciparum species-specific real-time PCR and 2.5% were positive for P. vivax by P. vivax species-specific real-time PCR. 18 samples that were found positive by microscopy for P. falciparum were found negative by real-time PCR, and were positive for P. vivax by P. vivax species-specific real-time PCR. Conclusions There is concordance rate of 86% between microscopy and the species-specific real-time PCR. In malaria endemic areas, adoption of high quality control procedures for microscopy, as gold standard in accurate diagnosis and species differentiation, with well trained staff following WHO criteria is needed