Protein-energy malnutrition (PEM) has been demonstrated in about 35% of patients with juvenile rheumatoid arthritis (JRA), but fewer than 8% of children with rheumatic diseases were reported in a national survey to have been seen by a pediatric dietitian. We demonstrate the development of a nutritional screening test for PEM in patients with JRA for use by all health care professionals. Nutritional assessment of 74 patients with JRA was conducted using a standardized 11 variable profile comprised of upper body anthropometric and biochemical measurements. The sensitivity, specificity, predictive values and index of validity were calculated for individual and selected clusters of nutritional variables to predict the need for referral for PEM compared to the independent review by 2 pediatric dietitians to refer or not refer to a dietitian for further evaluation or care. Arm circumference less than or equal to 10th percentile for age and sex matched norms was selected as the screening test for PEM in patients with JRA due to a combination of excellent measurement characteristics (sensitivity 0.80, specificity 0.86, positive predictive value 0.90, negative predictive value 0.73, index of validity 0.88) and ease of measurement.