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Hypertension/High Blood Pressure Health Center

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Renin Assay

How It Feels

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.


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 activity 1
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

WebMD Medical Reference from Healthwise

Last Updated: November 14, 2014
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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