The variability of blood pressure measurements in children.

This study examined the sources and amount of variation present in the blood pressures of 99 third grade children, using data collected from three repeated measurements made on three separate visits. The results highlight factors to consider when planning or evaluating studies designed to relate children's blood pressure levels to environmental conditions. Factors include variability both between and within children by visit and between observers; periodic restandardization of observers during the course of a study is desirable.