A string test is performed to detect the presence of intestinal parasites. A weighted gelatin capsule attached to a string is swallowed and left in place. After about 4 hours, the gelatin capsule is pulled out of the stomach by the string. Any bile, blood, or mucus remaining on the string is examined under the microscope for cell types and segments of parasites or eggs.
Review Date 4/10/2020
Updated by: Michael M. Phillips, MD, Clinical Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.