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

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.
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.
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.
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.