[Comparison of two rapid diagnostic tests in detection of malaria parasites]

Abstract

Objective: To compare the performance of two rapid diagnostic tests (RDTs) for malaria parasite detection.

Methods: Blood samples of 200 malaria patients and 60 non-malaria persons were collected from Yunnan and Shanghai, respectively. The sera were detected by gold-colloidal immunochromatography (GICA) and OptiMAL, and microscopy was used as gold standard in species identification. The sensitivity, specificity, minimum detection limit of the two RDTs was compared.

Results: Of the 260 samples, malaria parasites were found in 200 by microscopy, of which 100 each were Plasmodium falciparum and P. vivax, respectively. Compared with microscopy, the sensitivity and specificity of GICA and OptiMAL for the samples were 87.5% (175/200) and 93.3% (56/60), 95.5% (191/200) and 100.0% (60/60), respectively. The sensitivity and specificity of GICA and OptiMAL for detection of P. falciparum were 83.0% (83/100) and 96.9% (155/160), 90.0% (90/100) and 99.4% (159/160), respectively; and for detection of P. vivax, they were 89.0% (89/100) and 98.8% (158/160), 96.0% (96/100) and 97.5% (156/160), respectively. There was a significant difference in malaria detection between GICA and OptiMAL (chi2 = 8.23, P < 0.05). No statistical difference was found between the two RDTs in P. falciparum and P. vivax detection (P > 0.05). OptiMAL showed better result in detection of P. falciparum when the parasite density was higher. The minimum detection limit of the two RDTs was about 100-200 parasites/microl blood.

Conclusion: Compared to GICA, OptiMAL has higher sensitivity and specificity. However, GICA shows lower minimum detection limit and better reproducibility in blood samples with different densities than that of OptiMAL.