February 1st 2003ABSTRACT: The most common errors in measuring blood pressure (BP) are using the incorrect cuff size, not having the patient relax for 5 minutes before the measurement, and deflating the cuff too quickly. Observer bias may compound technical errors. When patients use the proper procedure, home BP measurements may be more reproducible than office measurements. Brachial artery-based monitors are more accurate than finger- or wrist-based instruments. To ensure that patients measure their BP correctly, observe their technique with their own monitors. Counsel patients to measure their BP at predetermined times and to have their monitors validated periodically.