SCREENING FOR INTESTINAL PARASITES - IS A SINGLE SPECIMEN VALID

To assess the validity of a single stool or perianal swab specimen whe n screening for potentially pathogenic parasites, 88 residents of a ce ntre for developmentally handicapped adults were screened by collectin g on alternate days three stool samples and pinworm swabs. Both sensit ivity and negative predictive values were so low that three samples we re required for some parasites. The species being screened for and its underlying prevalence must be considered before collecting only one s pecimen to reduce laboratory costs.