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The renin test measures the level of renin in blood.
Plasma renin activity; Random plasma renin; PRA
A blood sample is needed.
Certain medicines may affect the results of this test. Your doctor will tell you if you need to stop taking any medicines. Do not stop any medicine before talking to your doctor.
Medicines that can affect renin measurements include:
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 time of day and body position when blood is drawn.
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. These soon go away.
Renin is a protein (enzyme) released by special kidney cells when you have a decreased salt (sodium) level or low blood volume.
Test results can help guide your doctor in choosing the correct medicine. Salt-sensitive patients with high blood pressure associated with low renin levels respond well to diuretic medicines.
Normal values range from 0.2 to 3.3 ng/mL/hour.
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.
High levels of renin may be due to:
Low renin levels may be due to:
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:
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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.