Diagnosis of asymptomatic malaria during pregnancy is complicated by parasite sequestration to the placenta. Current Rapid Diagnostic Tests (RDTs) are inadequately sensitive for the detection of sub-microscopic infections and are therefore limited to diagnosis of clinical malaria. This poses a problem in populations where these infections predominate e.g pregnant women or travelers. More sensitive diagnostic tools are needed for diagnosis of asymptomatic infections and to accelerate malaria elimination worldwide. The new Alere™ Malaria Ag P.f Ultra-Sensitive RDT test (uRDT) has been developed to bridge this gap for sensitive screening of asymptomatic populations.
Here we will evaluate the performance of the uRDT for the first time in pregnant women.
300 archived samples from asymptomatic pregnant women in Timika, Indonesia will be used in this study. Samples were previously collected in a STOPMiP trial (2013-16) and comprise both red blood cell pellets and plasma, 200 of which are malaria positive and 100 negatives (previously confirmed by molecular test results). These will be tested by uRDT and the results will be compared to pLDH and HRP ELISAs as reference standards. Since the HRP ELISA is specific to P. falciparum and gene-deletions of these have been previously reported, it is important to include the pan-Plasmodium pLDH ELISA. RDTS and ELISAs will be performed according to manufacturer’s protocols and read by two technicians blinded and the whole study conducted according to STARD guidelines.
The described study is currently underway, and we will be able to present diagnostic accuracy (sensitivity/ specificity) at the conference.
Evaluation of the uRDT will contribute to malaria in pregnancy control policy decisions around its use and implementation for the detection of asymptomatic infections in pregnant women, where sequestration of parasites presents additional barriers to detection.