The relative concentrations of IgM and IgG to Schistosomamansoni soluble egg antigen (SEA) were evaluated as an indication of the clinical stages of infection. Serum samples and single blood drops on filter papers were obtained from each of 358 Egyptian school pupils. An ELISA was simultaneously performed on diluted sera and on the 24-hour buffer eluates of dry blood spots. The 2 samples gave similar results in all cases. One group of 33 early schistosomal subjects had IgM:IgG ratios > 1 in sera and blood spot eluates. A 2nd group of 225 chronic schistosomal subjects had IgM:IgG ratios < 1.