Ambulatory blood pressure monitoring (ABPM): A variety of fully validated, reliable, automated, and accurate monitors are available. Blood pressure measurements taken every 15 to 20 minutes are recorded over 24 to 48 hours. Oscillometric monitors are most commonly used and auscultatory monitors with or without ECG gating also give excellent results. Data downloaded from the monitor are generally divided into day (diurnal) or night (nocturnal) periods. Daytime (awake) ambulatory blood pressure (ABP) values are lower than clinic readings, 10% to 20% higher than nighttime (asleep) readings, and provides measures of SBP and DBP load (percentage of blood pressure readings exceeding the upper limits of normal for a given time period). As blood pressure is more closely related to the sleep-wake cycle rather than day and night, as illustrated by the blood pressure rhythm following the inverted cycle of activity in night-shift workers, the time of sleep and wake during ABPM should be recorded in the patient diary or objectively determined with a motion- logger (actigraph). Recently, monitoring has been approved for reimbursement in selected settings including the identification of white-coat hypertension (WCH). A consensus view on ABPM technique is available.148 While reproducibility on repeated ABPMs for group data is excellent, concerns regarding individual patient reproduc- ibility have been raised