calculated urine vanillylmandelic acid level absolute change in urine vanillylmandelic acid level 2013-06-14T16:22:11Z CMO:0001636 JSmith The difference in the amount of vanillylmandelic acid, the major urinary metabolite of adrenal and sympathetic catecholamines such as epinephrine and norepinephrine, in a specified sample of urine, the fluid waste product excreted by the kidneys, between two points in time or two conditions expressed as the result of the subtraction in and of itself without comparison by ratio with another quantity. 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 change in urine 3-methoxy-4-hydroxymandelic acid level absolute change in urine VMA level clinical_measurement_ontology