A comparison of triceps skinfold and upper arm circumference measurements taken in standard and supine positions.

Because hospitalized patients are often unable to assume the upright position recommended for anthropometric measurements, the effect of patient position on accuracy of triceps skinfold and arm circumference measurements was investigated. Three measurements of triceps skinfold and arm circumference were taken on the right arm of 74 patients by trained technicians with extensive experience in anthropometric evaluation using a Lange caliper and Inser-tape. Measurements were repeated in the supine position 5 hours later on the same day by the same observer. Mean triceps skinfold, arm circumference, and calculated arm muscle circumference values obtained in the upright position correlated highly with those obtained in the supine position. Differences were less than one measurement unit and not significant when compared using parametric (Student t-test) and non parametric (Wilcoxon Matched-Pairs Signed-Ranks Test) statistically analysis. This study indicates that triceps skinfold and arm circumference can be measured accurately, reproducibly, and comparably in the supine position when the patient is unable to assume the recommended upright stance.