Renin Assay

Plasma Renin Activity (PRA) Test

Results

A renin assay blood test is done to find the cause of high blood pressure (hypertension). The time of day and your position (standing, sitting, or lying down) before the blood sample is collected, your age, and the level of sodium in your blood all affect the test results.

Normal

Normal values may vary from lab to lab.

Plasma renin activity

Adult, ages 20–39 (upright position, normal-sodium diet):	0.1–4.3 nanograms per milliliter per hour (ng/mL/hr)
Adult, age over 40 (upright position, normal-sodium diet)	0.1–3.0 ng/mL/hr
Adult, ages 20–39 (upright position, low-sodium diet)	2.9–24.0 ng/mL/hr
Adult, age over 40 (upright position, low-sodium diet)	2.9–10.8 ng/mL/hr

High values

A high renin value can mean kidney disease, blockage of an artery leading to a kidney, Addison's disease, cirrhosis, excessive bleeding (hemorrhage), or malignant high blood pressure is present.

Low values

A low renin value can mean Conn's syndrome is present.

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Author:	Jan Nissl, RN, BS	Last 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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