Malarigen malaria Pf/Pv antigen rapid test: a simple and effective tool for diagnosis of malaria in the far-flung hilly areas of Bangladesh

Abstract

Microscopic visualization of malarial parasites on thick and/or thin film is considered as "Gold Standard" for diagnosis of malaria. But it needs skilled microscopist as well as good laboratory set up, which are scarce in Chittagong Hill Tracts (CHT) in Bangladesh. A study was carried out to evaluate the efficacy of a newly introduced Rapid Diagnostic Test (RDT) device based on immunochromatographic test (ICT) format, for malarial parasite. This study was carried out at Balipara, a remote village 64 km away from Bandarban Hill District headquarters, during January 2007 to September 2007. A total 271 patients who reported to Sickbay of 37 Rifle Battalion, Balipara were tested by MALARIAGEN MALARIA Pf/Pv Antigen Rapid Test kit on the spot. Thick & thin blood films were prepared and stained by laboratory technician at the sick bay, properly labeled, preserved and sent to pathologist working at Armed Forces Medical College, Dhaka Cantonment, Dhaka for microscopy. Three (1.11%) cases were excluded as control band of RDT were negative or test band appeared after long incubation. Six (2.22%) were excluded for poor quality of staining blood film. Among 262 cases malarial parasites were detected in 74(28.24%). Of these 62(83.78%) were Plasmodium falciparum and 12(16.22%) were Plasmodium vivax. Parasite count ranged from 2500/mµL to 527500/mµL with mean 67400/mµL (+/-93400). Among 262 cases, 97(37.02%) were positive for malarial antigen(s) in RDT. Of these 74(76.29%) were P. falciparum and 23(23.71%) were P. vivax. Overall sensitivity and specificity of RDT for detection of malarial antigen(s) irrespective of their species were 95.95% and 86.71% respectively with positive and negative predictive value 73% & 98% respectively. Relative to microscopy, the device has shown sensitivity 94.6% and specificity 88.52% for detection of P. falciparum with positive and negative predictive value 72% and 98% respectively. The device sensitivity and specificity for detection of P. vivax were 100% and 93.1% with respective positive and negative predictive value 47% and 100%. Malariagen Malaria Pf/Pv Antigen Rapid Test (RDT) performs as a better sensor and discriminator of malarial parasites and their species and appears to be an acceptable tool for diagnosis of malaria in symptomatic patient.