absolute change in systolic blood pressure absolute diurnal change in systolic blood pressure 2014-03-24T12:45:12Z Calculated measurement of a difference in the maximum arterial blood pressure, that is the pressure at the point of maximal contraction of the heart, between two points in time, one during the day and the other at night, expressed as a number (positive or negative), not as a ratio or percentage relative to another quantity. JSmith The term "absolute change" refers to the subtraction of one value from another, as opposed to a dissimilarity of two values expressed as a ratio or as a percentage. In this context it is not intended to necessarily imply the difference expressed as an absolute value |n|, that is, the numeric value of the difference without regard to its sign. absolute circadian change in systolic blood pressure systolic diurnal amplitude