Evaluation of the erythrocyte sedimentation rate in children presenting with limp, fever, or abdominal pain

An erythrocyte sedimentation rate (ESR) is commonly ordered as part of the evaluation of patients with nonspecific but potentially serious symptoms. To investigate the performance of ESR in this setting, we used a computerized database and medical chart review to identify children (n=299) with ESR done for a previously undiagnosed condition. Medical records were reviewed to determine symptoms at presentation, referral status, and subsequent diagnoses, which were classified as serious (n=93) or benign (n=206). We found that serious underlying disease was about 7 times as likely in patients with ESR>50 mm/hr (57/102) than in patients with ESR<20 mm/hr (7/89). Although the prevalence of serious disease was higher among referral patients, the likelihood ratios were similar for referral and primary-care patients. An erythrocyte sedimentation rate greater than 50 mm/hr was most informative in patients presenting with limp (likelihood ratio LR] =8.2) and abdominal pain (LR=6.0) and least informative in patients presenting with fever (LR=2.5). On the other hand, an ESR<20 mm/hr is reassuring in patients presenting with fever (LR=0) or limp (LR=0.3), but not in patients presenting with abdominal pain (LR=0.8). An ESR between 20 and 50 mm/hr (23% of the patients) provided little information (LR 1.2-1.5) in each of the three groups. These results suggest that the ESR often provides useful information about the likelihood of serious illness among children presenting with worrisome but nonspecific symptoms, in particular in patients presenting with limp.