Comparison of urine filtration and a chemical reagent strip in the diagnosis of urinary schistosomiasis in Ethiopia.

The diagnostic efficacy of a chemical reagent strip (Ames Multistix) was compared with syringe-Nytrel urine filtration technique in the detection of S. haematobium infection at varying disease endemicity levels in the Awash Valley of Ethiopia. In low endemicity area (Afambo), the reagent strip showed highest sensitivity, specificity, positive predictive value and negative predictive value of 80%, 96%, 40% and 99% respectively at "1+ limit" of microhaematuria. In the moderate (Dahitele) to high (Enta Doyta) areas, the highest diagnostic values of 77%, 83%, 56% and 93% respectively and 78%, 67%, 51% and 87% respectively were obtained at "trace limit". Using these cut-off points of haematuria, the prevalence of S. haematobium were 4.5%, 30.8% and 47% at low, moderate and high endemicity areas compared to 3.2%, 21% and 31% respectively using the filtration technique. A highly significant (maximum Kendall's tau = 0.44271; p < 0.002) was observed between N + 1 transformed geometric mean egg counts and micro-haematuria in the 10-19 years of age at all levels of endemicity. The efficacy and simplicity of chemical reagent strips and limitations of single parasitological examinations are discussed.