Renin
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Definition
Renin is a protein (enzyme) released by special kidney cells when you have decreased salt (sodium levels) or low blood volume.
Renin also plays a role in the release of aldosterone, a hormone that helps control the body's salt and water balance.
This article discusses the test to measure the activity of renin in your blood.
Alternative Names
Plasma renin activity; Random plasma renin; PRA
How the test is performed
A blood sample is needed. For information on how this is done, see: Venipuncture
How to prepare for the test
Your health care provider may tell you to temporarily stop taking certain drugs that can affect test results.
Drugs that can affect renin measurements include:
- Birth control pills
- Blood pressure medications
- Diuretics
- Vasodilators (drugs that enlarge blood vessels; they are usually used to treat high blood pressure or congestive heart failure)
You should eat a normal, balanced diet with moderate sodium content (about 3 gm/day) for 3 days before the test.
How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performed
This test is done as part of the diagnosis and treatment of high blood pressure.
If you have essential hypertension, your doctor may order a renin and aldosterone test to see if you are sensitive to salt (which causes low renin with normal aldosterone levels).
The test results may help to guide your doctor in choosing the correct medication. Salt-sensitive patients with high blood pressure associated with low renin levels respond well to diuretic medications.
References
Victor RG. Arterial hypertension. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 67.
Review Date: 8/21/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Alternative Names
Plasma renin activity; Random plasma renin; PRA
What the risks are
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)
Special considerations
Renin measurements are affected by salt intake, pregnancy, time of day, and body position.
References
Victor RG. Arterial hypertension. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 67.
Review Date: 8/21/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Alternative Names
Plasma renin activity; Random plasma renin; PRA
Normal Values
Normal values range from 0.2 to 3.3 ng/mL/hour.
The examples above are common measurements for results of these tests. 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
High levels of renin may be due to:
- Addison's disease
- Cirrhosis
- Congestive heart failure
- Dehydration
- Hemorrhage (bleeding)
- High blood pressure
- Hypokalemia
- Malignant hypertension
- Nephrotic syndrome
- Renin-producing renal tumors
- Renovascular hypertension
Low renin levels may be due to:
- ADH therapy
- Hyperaldosteronism
- Sodium-retaining steroid therapy
- High blood pressure that is sodium-sensitive
References
Victor RG. Arterial hypertension. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 67.
Review Date: 8/21/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Review Date: 8/21/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.