Acomparative Study Between Microscopy And An Immunochromatographic Test For The Diagnosis Of Malaria In Khartoum

Abstract

This study was conducted in Elkalakla area (south Khartoum) from February to July, 2001, to assess the performance and the comparative sensitivity an specificity of the ICT in the laboratory diagnosis of malaria. There were ninety-two patients, suspected of having malaria, enrolled in this study. Finger blood samples were tested with ICT dipstick and with microscopical examination of blood films, the comparative sensitivity and specificity of the ICT were calculated using the results of blood film examination as the gold standard, the intensity of parasitaemia was estimated by using W.H.O. crosses system. Microscopical examination of Giemsa stained blood.films revealed that 54 (58.7%) patients had the malaria parasite: Plasmodium falciparum in their peripheral blood while, the ICT revealed that there were 65(70.7%)who showed malaria-parasite antigen in their peripheral blood .Eleven patients who were negative by blood films examination were positive by the ICT; they were considered as false positives for the ICT and the persistent antigenaemia maybe a more probable cause of those false positive samples. There was no evidence of any positive-blood film that reacted negative in the ICT. Comparative results in this study showed that the ICT was 100% sensitive and 77.6 % specific when compared with microscopic examination of Giemsa-stained blood films for the diagnosis of malaria. So, it is avaluable diagnostic tool for malaria specially in emergency and field situations which require rapid diagnosis and treatment. The present study also compared specific data of the patients such as sex, age , fever symptom and treatment with the rate of positive of malaria infection by both techniques: microscopic examination of Giemsa-stained blood films and ICT. Results showed that there was no significant differences in the sex ratio in all samples .While the effect of age as a factor for acquisition of immunity against infection was confirmed by the results that revealed that the parasite positivity rate and density of infection decreased significantly with increase age. Results of fever revealed that there was a significant correlation between fever and the malaria infection rate, particularly with high level of parasitaemia. While there was strong association between pre-treated patients and the malaria infection rate in both positive blood films and positive ICT.