title: Application of rejection criteria for stool ovum and parasite examinations.
abstract: We retrospectively determined the yield of 2,015 stool ovum and parasite (O&P) examinations performed over an 11-month period. Two aspects were evaluated: the yield of positive results from multiple specimens per patient versus the result of a single examination, and the yield of positive results from stools submitted after 3 days of hospitalization. There were 131 (6.7%) positive O&P examinations from 75 patients: for 35 patients the single examination was positive; for 18, two of two examinations were positive; and for 15, three of three examinations were positive. The remaining seven patients had at least one negative examination in a series, but pathogenic intestinal parasites were detected in only three of these patients. Seventeen patients with positive O&P examinations were inpatients: seven of nine patients examined for O&P within 3 days of admission had stool specimens that contained recognized pathogens, in contrast to only two of eight patients examined after 3 days of hospitalization. After reviewing the data and informing hospital clinics, wards, and physicians, we instituted the following policy for screening stool specimens submitted for O&P examination. Only one O&P examination was performed for each outpatient visit and for inpatients hospitalized for 3 days or less, and examinations were not performed on stools submitted after 3 days of hospitalization unless the clinician arranged for the examination on the basis of clinical need. Over the 6-month follow-up period, 29.9% of O&P requests were rejected, 22% for patients in hospital for longer than 3 days and 7.9% for multiple O&P requests. Of 265 initially rejected specimens, 22 (8.3%) were examined after the referring physician contacted the laboratory. None of these specimens was positive. We conclude that eliminating O&P examinations of patients hospitalized for more than 3 days and initially performing only one examination per patient significantly reduces the number of examinations performed and reduces laboratory charges without adversely affecting patient care.
authors.affiliation: Clinical Microbiology Laboratory, Duke University Medical Center, Durham, North Carolina.
authors.forename: A J
authors.initials: AJ
authors.lastname: Morris
authors.forename: M L
authors.initials: ML
authors.lastname: Wilson
authors.forename: L B
authors.initials: LB
authors.lastname: Reller
mesh_terms: D000328:Adult; D000818:Animals; D003967:Diarrhea / Q000175:diagnosis / Q000469:parasitology*; D005069:Evaluation Studies as Topic; D005243:Feces / Q000469:parasitology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010270:Parasite Egg Count / Q000706:statistics & numerical data*; D010272:Parasitic Diseases / Q000175:diagnosis*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity