Appraisal of the acridine orange method for rapid malaria diagnosis at three Tanzanian district hospitals.
The need to have rapid and accurate confirmation of malaria parasitaemia prompted us to evaluate the direct Acridine Orange (AO) stain method in comparison to the traditional Giemsa Stain (GS) method in the detection of malaria parasites in patients with presumptive diagnosis of malaria. We evaluated the sensitivity and specificity of the AO method as well as the durability of the fluorescence microscope. Out of 400 patients with presumptive diagnosis of malaria, 209 (52.3%) and 197 (49.3%) had malaria parasites as detected by GS and AO methods respectively, the difference being statistically insignificant. The sensitivity and specificity of AO method compared to the gold standard (GS) method were 94.1% and 100% respectively. At parasite count below 5,000 per microlitre of blood, the sensitivity of AO method decreased to 90.2% but the difference was not statistically significant. The positive and negative predictive values were 100% and 94.1% respectively at all levels of parasite count. The mean duration to get results of malaria parasite diagnosis by GS and AO methods were 35 and 5 minutes respectively. The limitation of the AO method was frequent blowing of the fluorescence microscope bulb. It is concluded that if the bulb system of the fluorescence microscope can be improved, the AO method could be included among other methods for the detection of malaria parasites in clinical settings.
Tarimo
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DS
Department of Parasitology/Entomology, Muhimbili University College of Health Sciences, Dar es Salaam, Tanzania.
Mpembeni
R
R
Kawawa
H
H
Mshana
T C
TC
D000165:Acridine Orange; D001399:Azure Stains; D005456:Fluorescent Dyes; D006767:Hospitals, District; D006801:Humans; D008288:Malaria / Q000175:diagnosis* / Q000469:parasitology*; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013636:Tanzania; D013997:Time Factors
D001399:Azure Stains; D005456:Fluorescent Dyes; D000165:Acridine Orange