Phase I: A total of 3939 tests were ordered for the 285 patients entered in phase I. Aspartate aminotransferase and alanine aminotransferase values were obtained in 59% of patients; glucose level was obtained in 78% of patients; complete blood cell count, U/A, and levels of electrolytes, blood urea nitrogen, creatinine, amylase, and lipase were obtained in more than 85% of patients. The overall prevalence of laboratory abnormalities was 5.7%. Fourteen patients (4.8%) were identified who had a total of 23 significant IAIs (9 pancreatic, 6 splenic, 5 renal, 3 hepatic). The PE combined with U/A showing more than five red blood cells per high-power field had a sensitivity of 100%, specificity of 64%, positive predictive value of 13%, and negative predictive value of 100% for the detection of IAI. The presence of laboratory abnormalities suggesting injury did not increase the sensitivity of the model and significantly decreased both specificity and positive predictive value. Phase II: The PE combined with U/A identified an abnormality in 89 (97.8%) of 91 cases (95% confidence interval = 94.8% to 100%).Conclusions
In the moderately injured pediatric trauma patient, (1) there is a low prevalence of laboratory abnormalities; (2) the PE combined with U/A is a highly sensitive screen for IAI; and (3) in patients with a normal PE of the abdomen and a normal U/A, laboratory testing seldom identifies unsuspected IAI. Pediatrics 1993;92:691-694; intra-abdominal injury, trauma, laboratory testing, diagnosis.