Research procedures include collection of stool, blood and duodenal fluid when the diagnosis has been established and these procedures are not required for medical care. Patients with strongyloidiasis may also be given a diagnostic skin test similar to skin tests for tuberculosis and allergies. Research procedures on children will be limited to collection of stool, urine and blood. No more than 7 milliliters (1 1/2 teaspoons) per kilogram (2.2 pounds) body weight of blood will be collected in children over a 6-week period. In adults no more than 30 tablespoons of blood will be collected in a 6-week period.