Comparison of PfHRP-2/pLDH RDTs with Light Microscopy in a Low Prevalence Setting in Southeastern Iran, Sistan and Baluchestan: Due to Implementation of Malaria Elimination Program

Abstract

Background: The gold standard for diagnosing malaria in Iran is using light microscopy; however, this method requires equipment, time and skilled microscopists. In some circumstances, rapid diagnostic test (RDTs) can be a proper substitute. Assessing the diagnostic performance of RDT relative to microscopy, for the diagnosis of malaria in Southeastern Iran, Sistan and Baluchestan, was the purpose of this study. Methods: From March to July 2016, which was a peak transmission season in Iran, 318 patients with suspected malaria were taken for a blood sample at the health center in Saravan, in Sistan and Baluchestan Province. The samples were surveyed instantly by light microscopy and RDT. Comparison analysis included: sensitivity, specificity, positive and negative predictive values, and other diagnostic screening performance measures for detecting malaria infections. Results: Of the 318 malaria cases (6.6%), 21 were identified by a microscopy compared to 22 of 318 (6.9%) by RDT. RDT sensitivity and specificity for the diagnosis of malaria were 95.5% (77.2% - 99.9%, 95% CI) and 100% (98.8% - 100%, 95% CI), respectively, compared to standard microscopy, the sensitivity and specificity for vivax malaria were 100% (79.4-100%, 95% CI) and 99.7% (98.14% - 99.99%, 95% CI), and for falciparum malaria: 80% (28.4% - 99.5%, 95% CI) and 100% (98.8% - 100%, 95% CI). Two tests showed an amazing agreement with a kappa estimation of 0.975. Conclusions: The study proved that the RDT test performs appropriately for the identification of infections with P. falciparum and P. vivax malaria in cross-border malaria. Moreover, the RDT can be a useful instrument for the identification of new clinical cases of malaria in this region.