A Novel Immunochromatographic Test Strip Versus A Commercial Rapid Diagnostic Test for the Detection of Imported Plasmodium Species in Guangxi Province, China: A Comparative Evaluation

Abstract

Background: China has made significant progress towards malaria elimination by achieving zero reports of indigenous malaria cases over two consecutive years. The diagnosis of malaria, which is based on microscopic examination, still remains a challenge, due to a lack of sensitivity for detecting low-level parasitaemia. This study aimed to evaluate the diagnostic value of a novel immunochromatographic test strip for imported malaria. Methods: After obtaining informed consent, blood samples were collected from migrants returning home from Africa to Shanglin County in Guangxi, PR China, in 2018-2019, and were tested with the novel test strips. The test results were compared with those of microscopic examination, commercial malaria rapid diagnostic test (RDT), and polymerase chain reaction (PCR) assay. Results: A total of 535 samples were tested. Both microscopy and PCR test results showed a total of 162 (30.28%) malaria-positive samples, of which 99 were positive for Plasmodium falciparum (P. falciparum), three for P. vivax, five for P. malariae, and 50 for P. ovale, whereas five had mixed infections. The sensitivity, specificity, and efficiency of the novel RDT were 74.1%, 93.0%, and 87.3%, respectively, whereas its sensitivity of detecting P. falciparum, P. vivax, P. malariae, and P. ovale was 91.9%, 100%, 20.0%, and 44.0%, respectively. Furthermore, the sensitivity, specificity, and efficiency of the commercial RDT were 86.0%, 89.3%, and 88.2%, respectively, whereas its sensitivity of detecting P. falciparum, P. vivax, P. malariae, and P. ovale was 96.0%, 100%, 40.0%, and 70.0% respectively. The differential detection of Plasmodium species using the new RDT was significantly better compared to that of the commercial RDT (c2 = 14.73; P = 0.0001), which can detect only P. falciparum. This was consistent with Kappa analysis (Kappa = 0.881). A significant difference (c2 = 24.50; P < 0.0001) in the detection rate of other Plasmodium species was observed with an average consistency using Kappa analysis (Kappa = 0.716). Conclusion: The novel malaria RDT test strip had high sensitivity and specificity in detecting P. falciparum and P. vivax. Improvement in P. ovale and P. malariae detection efficiency may lead to the scale-up of this RDT in the future.