INTRODUCTION: The clinical assessment of unilateral limb lymphedema is commonly based on measurements of interlimb volume differences. Reference values for interlimb percentage differences of the volume, fat mass, and lean mass measured with dual-energy X-ray absorptiometry (DXA) scan are, however, not established. The aim of the study was to establish and categorize these reference values in normal limbs.

METHODS AND RESULTS: DXA scans of the normal arms of 167 and normal legs of 196 melanoma patients (aged 18-75 years, body mass index <40), respectively, were performed. The interlimb percentage difference is calculated as follows: ("Limb-of-interest"-contralateral)/contralateral × 100. The interlimb percentage differences for the limb-of-interest were stratified to upper (according to handedness) and lower limbs and categorized as none/mild, moderate, or severe, respectively, based on whether the value is below, in between, or above the two prediction limits. The prediction limits for interlimb total volume percentage difference were 6% and 10%, 0% and 4%, and 3% and 6% for the dominant arm, nondominant arm, and leg, respectively. Further data are given for interlimb percentage differences of regional (upper arm, lower arm, hand, thigh, lower leg, and foot) and total volume, fat mass, and lean mass, respectively.

CONCLUSIONS: The provided clinical reference values allow for identifying and categorizing pathophysiological differences of limbs-of-interest and evaluating tissue composition.