Renin Assay

Plasma Renin Activity (PRA) Test

How To Prepare

For 2 to 4 weeks before the test, you will be asked to stop taking medicines that can affect the test, such as diuretics, estrogens, and high blood pressure medicines (especially beta-blockers and ACE inhibitors). Your health professional may have you take other medicines for a few weeks that will not change the renin test results.

Do not eat natural black licorice for 2 weeks before the test. Do not eat or drink foods that contain caffeine the day before the test. Natural licorice and caffeine can change the test results.

For 3 days before a renin test, you may be asked to follow a special low-sodium diet.

You will be asked to not eat or drink anything for 8 hours before the test.


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Author: Jan Nissl, RN, BSLast Updated: September 15, 2006
Medical Review: Caroline S. Rhoads, MD - Internal Medicine
David C.W. Lau, MD, PhD, FRCPC - Endocrinology & Metabolism

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Topic Contents
 Test Overview
 Why It Is Done
Arrow PointerHow To Prepare
 How It Is Done
 How It Feels
 Risks
 Results
 What Affects the Test
 What To Think About
 References
 Credits