A comparison of peripheral blood smear microscopy and detection of histidine-rich protein 2 in blood in the diagnosis of malaria in pregnancy

Abstract

Background: Detection of malaria in pregnancy poses a huge challenge in Sub-Saharan Africa. Accurate diagnosis enables timely and appropriate clinical management. Aims: This study aimed to compare the accuracy of peripheral venous blood smear microscopy (PVBSM) and a rapid diagnostic test detecting histidine-rich protein 2 in the blood (RDT-HRP2) with placental histology as the control in the diagnosis of malaria in pregnancy in Nigerian women. Materials and Methods: This was a comparative, cross-sectional study conducted between January and July 2017. Asymptomatic pregnant women who presented to the labor ward and who gave informed consent had peripheral venous blood samples as well as placental tissue obtained following delivery. The blood samples obtained were tested for malaria parasites using PVBSM and RDT-HRP2 in blood, while the placenta was subjected to histology. Results: A total of 326 patients participated in the study. The prevalence of malaria in pregnancy was 13.8%, 17.8%, and 32.8% using PVBSM, RDT-HRP2, and placental histology. The sensitivity, specificity, and accuracy of PVBSM were 40.2%, 99.1%, and 79.8% and the corresponding values for RDT-HRP2 were 49.5%, 97.7%, and 81.9%. The positive predictive value was 95.6% for PVBSM and 91.4% for RDT-HRP2 and the negative predictive value was 77.2% for PVBSM and 79.9% for RDT-RP2. Conclusions: The diagnostic performances of both tests were comparable; however, RDT-HRP2 had a higher sensitivity and accuracy than PVBSM for the diagnosis of malaria in pregnancy.