The examination can be performed on a simple smear (1 to 2 mg of fecal material). Because eggs may be passed intermittently or in small numbers, their detection is enhanced by repeated examinations or concentration procedures, or both. In addition, for field surveys and investigational purposes, the egg output can be quantified by using the Kato-Katz technique (20 to 50 mg of fecal material) or the Ritchie technique. Eggs can be found in the urine in infections with S. haematobium (recommended time for collection: between noon and 3 PM) and with S. japonicum. Quantification is possible by using filtration through a nucleopore filter membrane of a standard volume of urine followed by egg counts on the membrane. Tissue biopsy (rectal biopsy for all species and biopsy of the bladder for S. haematobium) may demonstrate eggs when stool or urine examinations are negative.Identification of microhematuria in urine using urine reagent strips is more accurate than circulating antigen tests in the identification of active schistosomiasis in endemic areas. Antibody detection
Antibody detection can be useful to indicate schistosome infection in people who have traveled to areas where schistosomiasis is common and in whom eggs cannot be demonstrated in fecal or urine specimens.
Test sensitivity and specificity vary widely among the many tests reported for the serologic diagnosis of schistosomiasis and are dependent on both the type of antigen preparations used (crude, purified, adult worm, egg, cercarial) and the test procedure.At the U.S. Centers for Disease Control and Prevention, a combination of tests with purified adult worm antigens is used for antibody detection. All serum specimens are tested by FAST-ELISA using S. mansoni adult microsomal antigen. A positive reaction (greater than 9 units/µl serum) indicates infection with Schistosoma species. Sensitivity for S. mansoni infection is 99%, 95% for S. haematobium infection, and less than 50% for S. japonicum infection. Specificity of this assay for detecting schistosome infection is 99%. Because test sensitivity with the FAST-ELISA is reduced for species other than S. mansoni, immunoblots of the species appropriate to the persons travel history are also tested to ensure detection of S. haematobium and S. japonicum infections. Immunoblots with adult worm microsomal antigens are species-specific, so a positive reaction indicates the infecting species. The presence of antibody is indicative only of schistosome infection at some time and cannot be correlated with clinical status, worm burden, egg production, or prognosis. Where a person has traveled can help determine which Schistosoma species to test for by immunoblot.In 2005, a field evaluation of a novel handheld microscope was undertaken in Uganda for the diagnosis of intestinal schistosomiasis by a team led by Russell Stothard from the Natural History Museum of London, working with the Schistosomiasis Control Initiative, London.