Renin blood test
Plasma renin activity; Random plasma renin; PRAThe renin test measures the level of renin in blood.
How the Test is Performed
Blood sample is needed
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
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 (enzyme) released by special kidney cells when you have a decreased salt (sodium) level or low blood volume. Most often, the renin blood test is done at the same time as an aldosterone blood test to calculate the renin to aldosterone ratio.
Enzyme
Enzymes are complex proteins that cause a specific chemical change. For example, they can help break down the foods we eat so the body can use them....
If you have high blood pressure, your doctor may order a renin and aldosterone test to help determine the cause of your elevated blood pressure. Test results can help guide your doctor in choosing the correct treatment.
High blood pressure
Blood pressure is a measurement of the force exerted against the walls of your arteries as your heart pumps blood to your body. Hypertension is the ...
Aldosterone
The aldosterone blood test measures the level of the hormone aldosterone in blood. Aldosterone can also be measured using a urine test.
Normal Results
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 disease or other adrenal gland insufficiency)
Addison disease
Addison disease is a disorder that causes the adrenal glands to not produce enough hormones.
ImageRead Article Now Book Mark Article - Bleeding (hemorrhage)
- Heart failure
- High blood pressure caused by narrowing of the kidney arteries (renovascular hypertension)
Renovascular hypertension
Renovascular hypertension is high blood pressure due to narrowing of the arteries that carry blood to the kidneys. This condition is also called ren...
ImageRead Article Now Book Mark Article - Liver scarring and poor liver function (cirrhosis)
Cirrhosis
Cirrhosis is scarring of the liver and poor liver function. It is the last stage of chronic liver disease.
ImageRead Article Now Book Mark Article - Loss of body fluid (dehydration)
- Low salt diet
- Kidney damage that creates nephrotic syndrome
Nephrotic syndrome
Nephrotic syndrome is a group of symptoms and abnormal test results that include protein in the urine, low blood protein levels in the blood, high ch...
ImageRead Article Now Book Mark Article - Kidney tumors that produce renin
- Sudden and very high blood pressure (malignant hypertension)
Malignant hypertension
Malignant hypertension is very high blood pressure that comes on suddenly and quickly.
ImageRead Article Now Book Mark Article
A low level of renin may be due to:
- Adrenal glands that release too much aldosterone hormone (hyperaldosteronism)
Hyperaldosteronism
Hyperaldosteronism is a disorder in which the adrenal gland releases too much of the hormone aldosterone into the blood. Hyperaldosteronism can be pr...
ImageRead Article Now Book Mark Article - High blood pressure that is salt-sensitive
- High salt diet
-
Treatment with antidiuretic hormone (ADH)
Treatment with antidiuretic hormone
Antidiuretic blood test measures the level of antidiuretic hormone (ADH) in blood.
Read Article Now Book Mark Article - Treatment with steroid medicines that cause the body to retain salt
Risks
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)
References
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.
-
Kidney - blood and urine flow - illustration
This is the typical appearance of the blood vessels (vasculature) and urine flow pattern in the kidney. The blood vessels are shown in red and the urine flow pattern in yellow.
Kidney - blood and urine flow
illustration
-
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
-
Kidney - blood and urine flow - illustration
This is the typical appearance of the blood vessels (vasculature) and urine flow pattern in the kidney. The blood vessels are shown in red and the urine flow pattern in yellow.
Kidney - blood and urine flow
illustration
-
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 7/30/2023
Reviewed By: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
All rights reserved.