Screening laboratory tests for Crohn's disease.

The prevalence of abnormal values of initial screening laboratory tests was assessed for 24 children who eventually proved to have Crohn's disease. The screening tests included in this analysis were fecal alpha 1-antitrypsin (FA) concentration, erythrocyte sedimentation rate (ESR), total leukocyte count, serum albumin level, hemoglobin concentration, and qualitative testing of stool for the presence of blood. Of the 24 patients, 21 had abnormal FA values, 17 had anemia, 19 had an increased ESR, 14 had hypoalbuminemia, rectal bleeding was found in 8, and none had leukocytosis. All 24 patients had at least one abnormal screening test value; the most frequently abnormal result was the FA concentration. Pediatric patients without elevated FA values, anemia, a high ESR, bloody stools, or hypoalbuminemia are unlikely to have active Crohn's disease.