Specificity of circulating antigen detection for schistosomiasis mansoni in Senegal and Burundi

The specificity of schistosome circulating antigen detection was determined in negative individuals from two S. mansoni-endemic countries, Senegal and Burundi, and compared with results from Dutch control individuals. A nearl y absolute specificity was achieved for circulating anodic antigen (CAA) de tection in serum, irrespective of the target population or sample pretreatm ent method. Circulating cathodic antigen (CCA) detection in serum and urine resulted in a lower specificity than serum CAA detection. Apparent large d ifferences in specificity of CCA detection between countries were mainly du e to pretreatment methods. Apparently, the alkaline; heating pretreatment m ethod is not as effective as trichloroacetic acid (TCA)-pretreatment in rem oving (certain) interfering components, which may vary between populations. In view of the development of the urine CCA assay into a noninvasive scree ning test, a slightly lower specificity may still be acceptable. For precis e epidemiological analyses the highly specific serum CAA assay remains the method of choice.