Intra- and Interexaminer Reliability of Anthropometric Measurements of Term Infants

BACKGROUND: The reliability of anthropometric measurements of term infants has not been studied sufficiently to determine if these measurements are reliable enough to be used in clinical practice and research. This study described the intra- and interexaminer reliability of the following anthropometric measurements: weight (WT), head circumference (HC), chest circumference (CC), abdominal circumference (AC), mid-arm circumference (MAC), and length. METHODS: A convenience sample of 50 clinically stable term infants was studied. Two examiners obtained the six measurements twice using blank tape measures. The order of examiners was randomized and the examiners were masked to their own and the other examiners' measurements. RESULTS: The intraexaminer mean absolute differences were as follows: WT = 1.88, 3.28 g; HC = 0.29, 0.29 cm; CC = 0.50, 0.78 cm; AC = 0.71, 0.77 cm; MAC = 0.36, 0.39 cm; length = 0.92, 1.18 cm. The interexaminer mean absolute differences were as follows: WT = 1.94, 1.66 g; HC = 0.37, 0.36 cm; CC = 0.59, 0.72 cm; AC = 0.99, 0.77 cm; MAC = 0.41, 0.57 cm; length = 1.57, 1.47 cm. CONCLUSIONS: These findings indicate that intraexaminer differences tended to be smaller than interexaminer differences for all measures except weight, which remained stable for intra- and interexaminer comparisons. These findings also suggest that weight and head circumference were the most reliable measures, whereas length and mid-arm circumference were the least reliable measures.