Renin blood test
The renin test measures the level of renin in blood.
Plasma renin activity; Random plasma renin; PRA
How the Test is Performed
How to Prepare for the Test
Certain medicines may affect the results of this test. Your health care provider will tell you if you need to stop taking any medicines. Do not stop any medicine before talking to your provider.
Medicines that can affect renin measurements include:
- Birth control pills.
- Blood pressure drugs.
- Medicines that dilate blood vessels (vasodilators). These are usually used to treat high blood pressure or heart failure.
- Water pills (diuretics).
Your provider may instruct you to limit your sodium intake before the test.
Be aware that renin level can be affected by pregnancy, as well as the time of day and the body position when blood is drawn.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
Renin is a protein (
If you have
For normal sodium diet, normal value range is 0.2 to 1.6 ng/mL/hour (0.2 to 1.6 µg/L/hour) while lying down and 0.5 to 4.0 ng/mL/hour (0.5 to 4.0 µg/L/hour) while standing.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
A high level of renin may be due to:
- Adrenal glands that do not make enough hormones (
Addison diseaseor other adrenal gland insufficiency)
- Bleeding (hemorrhage)
- Heart failure
- High blood pressure caused by narrowing of the kidney arteries (
- Liver scarring and poor liver function (
- Loss of body fluid (dehydration)
- Low salt diet
- Kidney damage that creates
- Kidney tumors that produce renin
- Sudden and very high blood pressure (
A low level of renin may be due to:
- Adrenal glands that release too much aldosterone hormone (
- High blood pressure that is salt-sensitive
- High salt diet
Treatment with antidiuretic hormone(ADH)
- Treatment with steroid medicines that cause the body to retain salt
There is little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Multiple punctures to locate veins
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Guber HA, Oprea M, Russell YX. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 25.
Weiner ID, Wingo CS. Endocrine causes of hypertension: aldosterone. In: Johnson RJ, Floege J, Tonelli M, eds. Comprehensive Clinical Nephrology. 7th ed. Philadelphia, PA: Elsevier; 2024:chap 39.
Review Date: 07/30/2023
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