The measurement of blood pressure and pulse rate first in the supine, then in the sitting, and finally in the standing position. A significant change in both of these vital signs signifies hypovolemia or dehydration. A positive test result occurs if the patient becomes dizzy or loses consciousness; or if the pulse increases by 20 or more beats per minute and the systolic blood pressure drops by 20 mm Hg within 3 min of arising from supine to sitting position or from sitting to standing position.