The Relevance of the Technical Error of Measurement in Anthropometry: A Pilot Study from The Nutrifunction Project

Introduction. Anthropometry plays a crucial role in nutritional assessment, especially in clinical and research settings where lack of precision affects data reliability and patient care. However, the accuracy of these measurements is often overlooked when assessing nutritional status and health risks. This study aimed to assess the technical error of measurement (TEM) and evaluate the intra- and inter-observer measurement error of anthropometric measurements performed by the NutriFunction team—an ongoing multicentre study involving hospitalised patients and a comparative sample of community-dwelling individuals. Methods. Six trained interviewers assessed twelve anthropometric indicators (body weight, body and knee height, hand and middle-finger lengths, hand breadth, mid-arm, waist, and calf circumferences, triceps, calf, and adductor pollicis thickness) on eight volunteers following ISAK and other pre-standardized techniques. TEM, relative TEM (%TEM), and coefficient of reliability (R) were calculated. Results. Most results were adequate for experienced anthropometrists, except for hand breadth (%TEM=1.2) and knee height (%TEM=1.2) for anthropometrist #4, and middle-finger length (%TEM=1.3) for #5 in intra-observer variability (R range=0.6-1.0). Inter-observer variability showed unacceptable %TEM for hand length (%TEM=2.0, 2.5, 1.5) for anthropometrists #1, #2, and #5, hand breadth (%TEM=2.0) for #4, adductor pollicis thickness (%TEM=9.9, 14.5) for #1 and #2, and middle-finger length (%TEM=2.0) for #5 (R range: 0.3-1.0). For the beginner standard, intra-observer variability was acceptable across all points, but inter-observer variability was unacceptable for hand length (%TEM=2.5) and adductor pollicis thickness (%TEM=14.5) for anthropometrist #2. Conclusions. Most anthropometric measurements had acceptable TEM values for experienced anthropometrists, meaning that these measurements present the necessary precision for clinical assessment and diagnosis. Anthropometrist #2 should not perform hand length and adductor pollicis thickness measurements until further training and a new TEM study are completed. Regular training is essential to minimise errors and safeguard the quality and clinical utility of anthropometric data for assessment, diagnosis and treatment. Funding: Fellowship FCT (2023.01790.BD). and European Regional Development Fund (NORTE-01-0145-FEDER-000039).