Urine Test Evaluated for Schistosomiasis Diagnosis

Urine circulating cathodic-antigen (CCA) tests are available for diagnosing schistosomiasis in endemic areas.

The accuracy of a commercially available CCA cassette test (designated CCA-A) and an experimental formulation (CCA-B) have been assessed for diagnostic accuracy for Schistosoma mansoni.

A cross-sectional survey was carried out by scientists at the Swiss Tropical and Public Health Institute (Basel, Switzerland) in three settings of Côte d'Ivoire, where local investigators collaborated. Two of the settings designated A and B, are endemic for S. mansoni, whereas S. haematobium coexists in the third setting, designated C. Overall, 446 children, aged 8–12 years, submitted multiple stool and urine samples.

For S. mansoni diagnosis, stool samples were examined with triplicate Kato-Katz thick smears, whereas urine samples were tested with CCA-A (Rapid Medical Diagnostics; Pretoria, South Africa). The first stool and urine samples were additionally subjected to an ether-concentration technique and CCA-B, respectively. Urine samples were examined for S. haematobium using a filtration method, and for microhematuria using Hemastix dipsticks (Siemens Healthcare Diagnostics GmbH; Eschborn, Germany).

The sensitivity of triplicate Kato-Katz from the first stool and a single CCA-A test was 47.9% and 56.3% (setting A), 73.9% and 69.6% (setting B), and 94.2% and 89.6% (setting C). The respective sensitivity of a single CCA-B was 10.4%, 29.9%, and 75.0%. The specificity of CCA-A test was moderate (76.9%-84.2%); while the CCA-B assay was high (96.7%-100%). A concurrent S. haematobium infection or the presence of microhematuria did not influence the CCA-A test results for S. mansoni diagnosis.

The authors concluded that in the current study area of south Côte d'Ivoire, where the prevalence and intensity of S. mansoni are still high, partially explained by the prior lack of control efforts, the CCA-A can become a useful method for S. mansoni diagnosis in health centers at the periphery and schistosomiasis control programs. On the other hand, while the specificity of the CCA-B test was high, its current formulation cannot be recommended for S. mansoni diagnosis. The study was published November 2011 in the online journal Public Library of Science Neglected Tropical Disease.

Related Links:
Swiss Tropical and Public Health Institute
Rapid Medical Diagnostics
Siemens Healthcare Diagnostics GmbH