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Renin blood test
Plasma renin activity; Random plasma renin; PRA
The 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)
Eat a normal, balanced diet with moderate sodium content (no more than 3 grams a day) for 3 days 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.
Enzyme
Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For example, they can help break down the foods we eat ...
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
Normal values range from 0.2 to 3.3 nanograms per milliliter per hour (ng/mL/hour) or 0.056 to 0.92 nanograms per liter per second (ng/L/s).
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 occurs when the adrenal glands do 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...
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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)
-
Kidney damage that creates
nephrotic syndrome
Nephrotic syndrome
Nephrotic syndrome is a group of symptoms that include protein in the urine, low blood protein levels in the blood, high cholesterol levels, high tri...
ImageRead Article Now Book Mark Article -
Kidney tumors that produce renin
Kidney tumors that produce renin
Proximal renal tubular acidosis is a disease that occurs when the kidneys don't properly remove acids from the blood into the urine. As a result, to...
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Sudden and very high blood pressure (
malignant hypertension
)
Malignant hypertension
Malignant hypertension is very high blood pressure that comes on suddenly and quickly.
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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
-
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
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample 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
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
References
Bailey MA, Shirley DG, Unwin RJ. Renal physiology. In: Johnson RJ, Feehally J, Floege J. Comprehensive Clinical Nephrology . 5th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 2.
Gruber HA, Farag AF. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 24.
Oh MS. Evaluation of renal function, water electrolytes, and acid-base balance. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 14.
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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
-
High blood pressure
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Review Date: 8/29/2015
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
