RENIN, ACTIVITY (PLASMA RENIN ACTIVITY,PRA)
Patient Preparation: Angiotensin Converting Enzyme (ACE) inhibitors should be avoided, if possible, for at least 48 hours prior to collection. Sprironlactone (Aldactone) should be discontinued 4-6 weeks prior to testing. Patient should be on a normal sodium diet.
Draw blood in 2 lavender EDTA tubes. Spin, separate and send 2.5 mL plasma frozen in a screw-capped plastic vial. Indicate “plasma/lav top” on transport vial. Contact lab for dry ice for shipment.
Frozen 1 month
2-4 days Performed Mon, Wed, Thurs
Useful in the differential diagnosis of hypertension. Renin is suppressed in about 90% of patients with Conn’s syndrome (aldosteronism). Evaluation of the hypertensive patient with hypokalemia, hyperkaluria, low renin and high aldosterone. Most established use of the renin assay is for unilateral renal diseases. Certain patients with diabetes mellitus and hypertension have low renin, low aldosterone. One cause of hypokalemia, Bartter’s syndrome, has increased renin and aldosterone.