The contrast enema for Hirschsprung disease: predictors of a false-positive result.
OBJECTIVE
To examine predictors of a false-positive (FP) result on contrast enema (CE) for the diagnosis of Hirschsprung disease (HD).


METHODS
Retrospective analysis, over a 5-year period (1999-2004), of infants (<6 months of age) with suspected HD undergoing rectal biopsy following abnormalities identified on CE (transition zone [TZ], abnormal rectosigmoid ratio, microcolon, retained contrast, or mucosal irregularity).


RESULTS
One hundred twenty-nine patients underwent rectal biopsy following an abnormal CE. The FP rate was 48.5% (66 with HD). Age below 30 days (OR, 3.4; 95% CI, 1.1-10.3), female sex (OR, 3.4; 95% CI, 1.6-7.3), and absence of TZ (OR, 6.3; 95% CI, 2.6-15.3) were independently associated with an increased risk for FP on multiple variable logistic regression. A history of bilious emesis decreased the probability of FP (OR, 0.2; 95% CI, 0.06-0.5).


CONCLUSIONS
Transition zone, sex, age, and bilious emesis are important predictors of FP in those with suspected HD and CE abnormalities. With 100% incidence of FP, infants younger than 30 days with neither bilious emesis nor a TZ and female infants younger than 30 days with these features may represent a subpopulation in whom rectal biopsy can be avoided.
Diamond
Ivan R
IR
Division of General Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.
Casadiego
Giovanny
G
Traubici
Jeffrey
J
Langer
Jacob C
JC
Wales
Paul W
PW
D001706:Biopsy; D016009:Chi-Square Distribution; D003287:Contrast Media; D004733:Enema; D005189:False Positive Reactions; D005260:Female; D006627:Hirschsprung Disease / Q000000981:diagnostic imaging*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D011237:Predictive Value of Tests; D011859:Radiography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D003287:Contrast Media