Evaluation of the detection of Plasmodium falciparum infection in Urine, Plasma, Serum, and Dried Blood Spots using real-time Polymerase Chain Reaction among Febrile patients in Lagos, Nigeria

Access to timely and accurate diagnostic tests has a significant impact on the management of malaria disease which is a global concern. Polymerase chain reaction (PCR) detection of Plasmodium DNA is highly sensitive in diagnosing malaria. The specimen of choice for this assay has been whole blood samples from patients with malaria caused by Plasmodium species. Nucleic acids can also be detected in urine, serum, plasma, and Dried Blood Spots (DBS) samples but there are few studies describing the diagnostic performance of PCR. Therefore, this study was aimed at evaluating the performance of real-time PCR (qPCR) in detecting malaria parasite DNA in serum, plasma, urine, and DBS. A cross-sectional study was conducted among 146 patients that attended the clinic at Bayeku, Oreta, Imota, Ijede, Agura Primary Health Centres (PHC) and Ikorodu General hospital of Lagos State. Urine samples and a total of 5 ml of blood were collected from each participant and made into dried blot spots, plasma, and serum. The samples were screened and assayed for Plasmodium falciparum by microscopy and Multiplex qPCR respectively. The sensitivity of qPCR using plasma, serum and urine specimens were 100%, 87%, and 52.6% respectively, while the specificity was 82%, 87.5% and 80% respectively. Parasite detection by microscopy showed greater agreement with detection by qPCR in serum (79.4%) than qPCR from plasma (75%) or urine (58.3%). In conclusion, malaria detection using qPCR assay on plasma has high sensitivity and can be used as an alternative to microscopy. © Parasitology and Public Health Society of Nigeria, 2023.