The use of routine laboratory studies as screening tools in pediatric abdominal trauma.

Background: Standard laboratory panels were shown to play an important role in the evaluation of pediatric blunt abdominal trauma before the routine use of computed tomography (CT) scan. Recently, only a few relatively limited studies have evaluated the use of these "trauma panels."

Objective: To evaluate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of routine "trauma panels" for evaluating intra-abdominal injury in pediatric blunt trauma patients.

Method: We undertook a retrospective medical record review of all children with potential major blunt abdominal trauma who entered the Children's Hospital (Boston, MA) trauma registry from July 1996 to August 1999. Routine laboratory tests during those years included sodium, glucose, white blood cell count, hematocrit, platelets, prothrombin time, activated partial thromboplastin time, aspartate aminotransferase (AST), alanine aminotransferase, amylase, lipase, and urinalysis. Individual findings were considered abnormal if they fell out of the laboratory's respective reference range. We determined sensitivity, specificity, PPV, NPV, and the 95% confidence interval for each test, using abdominal pathology identified by CT scan as the gold standard.

Results: Three hundred eighty-two patients were included. Of that, 68% were men. Median age was 115 months (intraquartile range, 60-159 months). In total, 241 of the patients (63%) had an abdominal CT scan performed, 83 of which (33%) had abnormal findings. Abnormal values for glucose, AST, urinalysis, and white blood cell count were the most frequently observed abnormalities (67%, 47%, 43%, and 43%, respectively). Among the 83 patients with abdominal pathology, glucose and AST had the highest sensitivity (75% and 63%, respectively). Lipase had the highest PPV at 75%, and AST had the highest negative predictive at 71%. No routine laboratory test had excellent sensitivity, specificity, PPV, and NPV.

Conclusions: Routine "trauma panels" should not be obtained as a screening tool in children with blunt trauma being evaluated for intra-abdominal injury.