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Renin Assay


There is very little chance of a problem from having a blood sample taken from a vein.

  • You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
  • In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
  • Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.


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.


The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Plasma renin activity1
Adult (upright position, normal-sodium diet)

0.7–3.3 nanograms per milliliter per hour (ng/mL/hr) or 0.7–3.3 micrograms per liter per hour (mcg/L/hr)

Adult (lying down, normal-sodium diet)

0.2–1.6 ng/mL/hr or 0.2–1.6 mcg/L/hr

Adult (upright position, low-sodium diet)

4.2–19.8 ng/mL/hr or 4.2–19.8 mcg/L/hr

Adult (lying down, low-sodium diet)

0.4–3.2 ng/mL/hr or 0.4–3.2 mcg/L/hr

Many things can affect renin test results. Your doctor will talk with you about any abnormal results that may be related to your symptoms and past health.

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 some types of kidney disease or Conn's syndrome is present.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Eating natural black licorice in the 2 weeks before the test.
  • Taking some medicines used to treat high blood pressure.
  • Taking aspirin, caffeine, estrogens, or diuretics.
  • Your position (standing, sitting, or lying down) before the test is done or the time of day when the blood sample is drawn, as well as recent salt intake.
  • Taking very high doses of corticosteroids.
  • Being pregnant.

WebMD Medical Reference from Healthwise

Last Updated: June 20, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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