In chronic infection, duration of symptoms is greater than 1-2 months. Abdominal pain is the more common complaint. In children, pain is variable with regards to location, duration, and character. No specific findings are present on physical examination. General abdominal tenderness may be noted in some children.
Blood tests Blood tests are usually normal.
The usual method for confirming the diagnosis is examination of a permanently stained smear of fresh feces, preserved immediately, for the morphologic characteristics of D fragilis trophozoites. Newer, but largely experimental, techniques include immunofluorescence techniques. Immediate preservation is necessary because in unpreserved feces, the morphologic characteristics of the trophozoites do not persist, and they round up and become granular within 15 minutes at room temperature. Ensure that stool samples are collected on alternate days since D fragilis can be excreted in a cyclic pattern similar to G lamblia . The final portion of the stool evacuation may contain the most concentrated numbers of trophozoites.