PURPOSE: Variability of ankle brachial index (ABI) measured by the same observer in the same individual on three different occasions was examined. BASIC METHODS: A single morning ABI was initially determined (measurement 1) with handheld Doppler device. One to four weeks apart, another morning (measurement 2) and afternoon (measurement 3) ABI was measured on the same day. PRINCIPAL FINDINGS: A total of 161 adults were enrolled. Mean ABI was similar among the three measurements. ABI differed more than ≥0.15 in 15 individuals between measurement 1 and 3, in 10 subjects between measurement 1 and 2, and in 12 individuals between measurement 2 and 3. Intra-group correlation coefficients of reproducibility of ABI were 0.808 for single measurements (coefficient of the values lacking association with each other), and 0.927 for average measurements (coefficient of the values that were associated with each other). CONCLUSIONS: Although reproducibility of ABI values was found satisfactory, up to 12% of participants displayed more than 0.15 alternations between measurements, either on the same day or more than a week apart.
PURPOSE: Variability of ankle brachial index (ABI) measured by the same observer in the same individual on three different occasions was examined. BASIC METHODS: A single morning ABI was initially determined (measurement 1) with handheld Doppler device. One to four weeks apart, another morning (measurement 2) and afternoon (measurement 3) ABI was measured on the same day. PRINCIPAL FINDINGS: A total of 161 adults were enrolled. Mean ABI was similar among the three measurements. ABI differed more than ≥0.15 in 15 individuals between measurement 1 and 3, in 10 subjects between measurement 1 and 2, and in 12 individuals between measurement 2 and 3. Intra-group correlation coefficients of reproducibility of ABI were 0.808 for single measurements (coefficient of the values lacking association with each other), and 0.927 for average measurements (coefficient of the values that were associated with each other). CONCLUSIONS: Although reproducibility of ABI values was found satisfactory, up to 12% of participants displayed more than 0.15 alternations between measurements, either on the same day or more than a week apart.