Yield from stool testing of pediatric inpatients
S. B. Meropol, A. A. Luberti and A. R. De Jong
Department of Pediatrics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, USA.
OBJECTIVES: To quantify the yield from stool testing in pediatric
inpatients and to identify criteria to test stool more deliberately without
sacrificing diagnostic sensitivity. DESIGN: A retrospective review was
performed of all stool cultures, ova and parasite examinations, and
Clostridium [correction of Clostridia] difficile toxin assays performed on
pediatric inpatients, aged 3 days to 18 years, at Thomas Jefferson
University Hospital, Philadelphia, Pa, for 1 year. Medical records were
reviewed for positive cases, each with 2 controls matched for age and test
type. For this study, the term admission refers to the interval between the
times each patient was admitted to and discharged from the hospital. Some
patients had multiple stool tests sent to the laboratory during a single
admission; some patients had more than 1 admission during the study period.
Statistical analysis was performed using X2 analysis and the Student
2-tailed t test with a commercially available statistical software package
(Statworks, Cricket Software, Philadelphia). RESULTS: Of 250 patient
admissions to the hospital for which stool was cultured, 7 cultures (2.8%)
were positive. Of 63 patient admissions having ova and parasite testing, 1
(2%) had a positive result. Clostridium [correction of Clostridia]
difficile toxin assays were performed on 40 patient admissions to the
hospital, and 7 (18%) had a positive result. Only 18 (3.0%) of 598 of all
test results reviewed were positive. Costs of negative test results totaled
$26,084. More patients (71%) with positive stool cultures than control
patients (21%) had a temperature higher than or equal to 38 degrees C (X2,
P < .05); however, relying on this sign missed 29% of the children with
bacterial infection. A white blood cell band count of at least 0.10 was
100% sensitive and 79% specific in identifying patients with positive stool
culture. There was no statistically significant relationship between stool
culture results and age, total white blood cell count or white blood cell
segmented neutrophil count, and no relationship between C. difficile toxin
assay results and any of the above characteristics. Clostridium [correction
of Clostridia] difficile was the most common pathogen identified (6 of 9)
in patients developing gastrointestinal symptoms after admission; however,
Salmonella enteritidis and Shigella sonnei were also significant causes (3
of 9). CONCLUSIONS: There is low yield from stool testing of pediatric
inpatients: C. difficile toxin assay has the highest yield. Clostridium
[correction of Clostridia] difficile testing is most valuable for children
with nosocomial gastrointestinal symptoms although other bacterial
pathogens do cause nosocomial symptoms in children. More selective stool
testing could help us be more efficient with our patient care resources.
