Emerg Radiol (2010) 17:353-360
Meir H. Scheinfeld , Soham Mahadevia, Evan G. Stein, Katherine Freeman, Alla M. Rozenblit
Abstract We sought to determine whether laboratory parameters could be found, predictive of a negative abdominal CT scan in young adults with nontraumatic abdominal pain. Following institutional review board approval, we evaluated CT reports of 522 patients, aged 21-35 years old, who presented to the Emergency Department with nontraumatic abdominal pain. Bivariate analyses relating ten laboratory parameters to whether the CT detected a cause for abdominal pain were conducted. A multivariate logistic regression model was then derived, with all variables in the final model significant at p<0.05. Variables were dichotomized to yield odds ratios and 95% confidence intervals. Of the 522 patients meeting inclusion criteria, 45% had a cause for pain demonstrated by CT. Predictors of a negative CT in men were normal hematocrit and negative urine blood (p=0.045,p=0.016, respectively), and in women normal hematocrit, granulocyte percent, and alkaline phosphatase (p=0.023, p=0.039, p<0.0001, respectively). When standard normal values were used to calculate descriptive statistics, only granulocyte percent in women had a significant confidence ratio (odds ratio 2.5, confidence interval 1.6-4.0). Among the 208 women with normal granulocyte percent, the final clinical diagnosis was appendicitis, cholecystitis, and diverticulitis, in three, three, and two cases, respectively (4% combined). In summary, no laboratory test was sufficient to offer reassurance that a CT is not necessary in a young adult patient with nontraumatic abdominal pain. Alternative strategies should be considered to decrease the use of CT, and its associated radiation exposure, in young adults with nontraumatic abdominal pain.