Multiplex Human Malaria Array: Quantifying Antigens for Malaria Rapid Diagnostics

Abstract

Malaria antigen detection through rapid diagnostic tests (RDTs) is widely used to diagnose malaria and estimate prevalence. To support more sensitive next-generation RDT development and screen asymptomatic malaria, we developed and evaluated the Q-Plex^™ Human Malaria Array (Quansys Biosciences, Logan, UT), which quantifies the antigens commonly used in RDTs-<i>Plasmodium falciparum</i>-specific histidine-rich protein 2 (HRP2), <i>P. falciparum-</i>specific lactate dehydrogenase (<i>Pf</i> LDH), <i>Plasmodium vivax</i> <i>-</i>specific LDH (<i>Pv</i> LDH), and Pan malaria lactate dehydrogenase (Pan LDH), and human C-reactive protein (CRP), a biomarker of severity in malaria. At threshold levels yielding 99.5% or more diagnostic specificity, diagnostic sensitivities against polymerase chain reaction-confirmed malaria for HRP2, <i>Pf</i> LDH, <i>Pv</i> LDH, and Pan LDH were 92.7%, 71.5%, 46.1%, and 83.8%, respectively. <i>P. falciparum</i> culture strains and samples from Peru indicated that HRP2 and <i>Pf</i> LDH combined improves detection of <i>P. falciparum</i> parasites with <i>hrp2</i> and <i>hrp3</i> deletions. This array can be used for antigen-based malaria screening and detecting <i>hrp2/3</i> deletion mutants of <i>P. falciparum</i>.