Comparison of blood smear microscopy to a rapid diagnostic test for in-vitro testing for P. Falciparum malaria in Kenyan school children

Abstract

Objective: To compare the diagnostic performance of microscopy using Giemsastained thick and thin blood smears to a rapid malaria dipstick test (RDT) in
detecting P. falciparum malaria in Kenyan school children.
Design: Randomised, controlled feeding intervention trial from 1998-2001.
Setting: Rural Embu district, Kenya. The area is considered endemic for malaria, with
four rainy seasons per year. Chloroquine resistance was estimated in 80% of patients.
Children had a spleen rate of 45%.
Subjects: A sample of 515 rural Kenyan primary school children, aged 7-11 years, who
were enrolled in a feeding intervention trial from 1998-2001. Main outcome measures: Percent positive and negative P. falciparum malaria status, sensitivity, specificity and positive and negative predictive values of RDT.
Results: For both years, the RDT yielded positive results of 30% in children compared
to microscopy (17%). With microscopy as the “gold standard,” RDT yielded a sensitivity
of 81.3% in 1998 and 79.3% in 2000. Specificity was 81.6% in 1998 and 78.3% in 2000.
Positive predictive value was 47.3% in 1998 and 42.6% in 2000, and negative predictive
value was 95.6% in 1998 and 94.9% in 2000.
Conclusion: Rapid diagnostic testing is a valuable tool for diagnosis and can shorten
the interval for starting treatment, particularly where microscopy may not be feasible
due to resource and distance limitations.

East African Medical Journal Vol. 85 (11) 2008: pp. 544-549