Plasma renin activity (PRA), also called plasma renin assay, may be used to screen for high blood pressure (hypertension ) of kidney origin, and may help plan treatment of essential hypertension
Risks for this test are minimal, but may include slight bleeding from the puncture site, fainting or feeling lightheaded after venipuncture, or hematoma (blood accumulating under the puncture site).
since renin is affected by body position, as well as by diurnal (daily) variation, blood samples should be drawn in the morning, and the position of the patient (sitting or lying down) should be...
Patients taking diuretics, antihypertensives, vasodilators, oral contraceptives, and licorice should discontinue use of these substances for two to four weeks before the test.