Evaluation of reagent strips in urine tests for detection of Schistosoma haematobium infection: a comparative study in Ghana and Zambia.

The presence of haematuria and proteinuria, detected by reagent strips, was compared with Schistosoma haematobium egg counts in the urines of human subjects from two epidemiologically distinct areas in Ghana and Zambia. In children and adults in both areas, the individual or combined semiquantitative levels of proteinuria and haematuria were related directly to increasing urinary egg counts. In both areas the presence of blood in the urine was highly specific (greater than 85%) and sensitive, being positive in 97% of urine specimens with more than 64 eggs per 5-ml sample of urine. The sensitivity of the protein indicator was also high, but its specificity was less than the blood indicator. The specificity of combined proteinuria and haematuria was higher than either alone; on the other hand, the sensitivity was lower than either alone. At each level of proteinuria and haematuria, the geometric mean urinary egg count was higher in Ghana than in Zambia. This study confirms the necessity to evaluate indirect diagnostic techniques in each endemic country, in order to establish criteria for their interpretation, before wide-scale use.

Indirect screening for Schistosoma haematobium infection: a comparative study in Ghana and Zambia.

Four indirect approaches, based on inquiry into a past history of haematuria, visual inspection for blood in the urine specimens, and the use of reagent strips to detect haematuria and proteinuria, were evaluated to identify persons with Schistosoma haematobium infection. These approaches were applied individually and in three different screening sequences on two populations in Ghana and Zambia in order to identify infected children and adults for subsequent treatment in both areas. Detection of haematuria using reagent strips was the single approach with the highest sensitivity and specificity. The observation of gross haematuria (bloody urine), followed by detection of blood by reagent strips, identified 87% of infected children in both areas. This screening sequence showed the highest combined sensitivity and specificity in the identification of infected children as well as adults for treatment in both areas. Differences in the results between the two countries are discussed. This study emphasizes the need for evaluation of indirect screening procedures for the diagnosis of S. haematobium infection in each endemic area so as to establish criteria for their interpretation, prior to large-scale field application.