Specimen Requirements

Stability

Days Performed

Sun - Sat

Turnaround Time

1 - 3 days

Methodology

Clinical Info

Malaria is a mosquito-borne disease caused by Plasmodium parasites, which are a major cause of illness and death globally. Malaria can also affect travelers from non-endemic areas. The primary Plasmodium species responsible for malaria are P. falciparum, P. vivax, P. malariae, and P. ovale. P. knowlesi, a simian parasite, has also been known to infect humans in parts of Southeast Asia and is significant due to its potential to cause severe illness. Initial diagnosis of malaria should be made using a rapid method, such as a lateral flow immunoassay, and/or microscopic exam of thick and thin blood smears. Thick film microscopy is used for screening, while thin films help determine percent parasitemia, which indicates the severity and helps monitor treatment response. Accurate determination of the Plasmodium species causing infection is critical, as it influences treatment choice and prognosis. Nucleic acid amplification testing can be used to confirm a presumptive malaria diagnosis and determine the species causing infection after a positive antigen test or morphologic exam with suboptimal morphology. This Plasmodium species Differentiation PCR is a lab-developed multireaction multiplex real-time PCR test performed on EDTA whole blood. The assay utilizes the RealStar Malaria Screen & Type PCR Kit 1.0 (Altona Diagnostics), and can simultaneously detect and differentiate between P. falciparum, P. vivax, P. malariae, P. ovale, and P. knowlesi. This test can be used in patients with a confirmed or presumptive diagnosis of malaria to determine the Plasmodium species causing infection. It should not be used as a primary screening test for malaria, or to monitor response to treatment. Within Cleveland Clinic, this test is only available as an add-on order to a positive malaria antigen screen or blood parasite microscopy smear.

Clinical Limitation

This assay does not have adequate turnaround time to be used as a screening test for malaria, and cannot be used to determine percent parasitemia. This assay may be unable to detect a specific Plasmodium species in the setting of amplification inhibition, very low-level parasitemia, mutations within target regions of organism genomes, or in a patient who does not have malaria. In the setting of mixed infections, the minor component(s) may not be reliably identified. Primarily zoonotic species Plasmodium brasilianum and Plasmodium inui may cause cross-reactivity with P. malariae or P. vivax targets respectively. This assay may be positive in asymptomatic patients with low-level parasitemia from malaria-endemic regions, and may continue to detect residual nucleic acid after adequate treatment. It should not be used for treatment monitoring.

Clinical Reference

1. Mathison BA, Pritt BS. Update on Malaria Diagnostics and Test Utilization. J Clin Microbiol. 2017 Jul;55(7):2009-2017. doi: 10.1128/JCM.02562-16. Epub 2017 Apr 12. PMID: 28404673 2. Aschar M, Sanchez MCA, Costa-Nascimento MJ, Farinas MLRN, Hristov AD, Lima GFMC, Inoue J, Levi JE, Di Santi SM. Ultrasensitive molecular tests for Plasmodium detection: applicability in control and elimination programs and reference laboratories. Rev Panam Salud Publica. 2022 Mar 28;46:e11. doi: 10.26633/RPSP.2022.11. PMID: 35355692