The renin-angiotensin system is also involved in red blood cell production and abnormal thickening of the heart muscle hypertrophy [ 6 ]. While high renin can increase blood pressure via the RAS, low renin can also increase blood pressure [ 7 ]. Plasma renin activity is a measure of the capacity of renin to generate angiotensin I precursor of angiotensin II [ 1 ]. A reference range includes the upper and lower limits of a lab test based on a group of otherwise healthy people.
Your healthcare provider will compare your lab test results with reference values to see if any of your results fall outside the range of expected values. By doing so, you and your healthcare provider can gain clues to help identify possible conditions or diseases.
Normal plasma renin activity PRA levels range from 0. Some lab-to-lab variability occurs due to differences in equipment, techniques, and chemicals used. Your doctor will interpret your results in conjunction with your medical history and other test results. Your doctor will interpret this test, taking into account your medical history and other tests.
Causes shown here are commonly associated with low renin. Work with your doctor or other health care professional for an accurate diagnosis. This may be a result of age-related structural changes in the kidneys and decreased renin production [ 1 , 7 , 13 , 14 ]. Low plasma renin activity is common in younger people of African descent, which is attributed to reduced renin production.
Because high blood volume inhibits renin production, fluid overload hypervolemia leads to low blood renin levels [ 7 ]. Renin levels are reduced in approximately a quarter of patients with essential hypertension. This is thought to be due to higher blood pressure at the cells that produce renin juxtaglomerular cells , which suppresses renin release [ 7 ]. Conditions that lead to kidney cell nephron loss and dysfunction can lead to low renin and aldosterone levels. These include [ 7 ]:. Blood renin activity levels were lower in 15 people with hypothyroidism compared to healthy people.
Scientists believe this may be a result of decreased renin production, in part owing to decreased sympathetic activity in the kidney i. Thyroid hormone treatment increased plasma renin activity levels in a study of 22 people with primary myxoedema severe hypothyroidism [ 22 ]. Primary hyperaldosteronism is when the adrenal glands release too much aldosterone hyperaldosteronism , resulting in increased potassium loss and sodium retention.
In turn, the excess sodium holds on to water, thereby increasing blood volume and pressure [ 7 ]. Over time, the increase in blood volume and pressure suppresses renin production. For this reason, people with primary hyperaldosteronism generally have very low renin levels as well as high aldosterone levels. They often also have low potassium levels [ 7 , 23 ].
Low renin levels differentiate primary i. Salt-sensitive high blood pressure is a condition in which blood pressure rises when excess salt is consumed and falls when salt intake is reduced [ 25 , 26 ]. Normally, a high-salt diet suppresses renin production.
Research suggests that many other factors may influence how blood pressure responds to salt, including [ 14 , 5 , 26 ]:. For these people, reducing salt intake is considered to be effective in lowering blood pressure [ 28 ]. Excess cortisol levels can activate certain receptors in the kidney mineralocorticoid receptors , which leads to potassium excretion and sodium and water retention.
Reviewed by: David C. Editorial team. How the Test is Performed A blood sample is needed. How to Prepare for the Test Certain medicines may affect the results of this test. 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.
How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. 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. Normal Results For normal sodium diet, normal value range is 0.
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 Bleeding hemorrhage Heart failure High blood pressure caused by narrowing of the kidney arteries renovascular hypertension Liver scarring and poor liver function cirrhosis Loss of body fluid dehydration Kidney damage that creates nephrotic syndrome Kidney tumors that produce renin Sudden and very high blood pressure malignant hypertension A low level of renin may be due to: Adrenal glands that release too much aldosterone hormone hyperaldosteronism High blood pressure that is salt-sensitive Treatment with antidiuretic hormone ADH Treatment with steroid medicines that cause the body to retain salt.
Risks There is little risk involved with having your blood taken. Your doctor will interpret this test, taking into account your medical history and other tests. Causes shown here are commonly associated with high renin.
Work with your doctor or other health care professional for an accurate diagnosis. An upright body posture slightly decreases blood pressure, which stimulates renin production. The renin-angiotensin system RAS is more active during pregnancy. In early pregnancy, the kidneys produce more renin and the ovaries and uterine lining produce an inactive renin precursor prorenin.
Also, as the placenta grows, it produces estrogen , which increases angiotensinogen production by the liver, leading to increased blood angiotensin II [ 7 , 8 , 9 ]. Because of an increase in aldosterone and other hormonal changes, pregnant women have higher blood volume [ 10 ]. Stress increases sympathetic activity, which stimulates renin production. In a study of 20 people 10 with high blood pressure, 10 healthy , mental stress increased plasma renin activity in both groups [ 11 , 12 ].
In a study of 33 runners, plasma renin activity increased 3-fold after a marathon run [ 13 ]. Plasma renin activity levels were elevated in 24 people with hyperthyroidism likely due to increased sympathetic activity [ 14 ]. Adrenal glands that do not make enough aldosterone and other hormones e. This is because a lack of aldosterone leads to increased sodium excretion, which lowers blood sodium levels and subsequently, blood volume and pressure.
This drop in blood sodium levels activates renin production in the kidney [ 15 ]. Renal artery stenosis, or the narrowing of one or both of the arteries that carry blood to the kidneys, decreases kidney blood flow.
This drop in blood flow stimulates renin production [ 19 , 20 ]. Hardening of the arteries atherosclerosis is the most common cause of renal artery stenosis [ 20 ].
Malignant hypertension is defined as sudden and very high blood pressure that causes organ damage. This may occur due to the damage of small kidney blood vessels caused by severe hypertension, which results in reduced blood flow in the kidneys. This activates renin production, which in turn may result in further blood vessel damage [ 21 ].
Reninomas are rare tumors of the kidney cells that make renin juxtaglomerular cell tumors. They produce excessive amounts of renin, resulting in severe hypertension, high aldosterone levels, and low blood potassium levels [ 22 , 23 ]. Liver scarring cirrhosis promotes fluid buildup within the abdomen ascites. This leads to decreased circulating blood volume, which stimulates renin production [ 24 ]. Pheochromocytoma is a rare, usually benign tumor that develops in the adrenal gland.
It causes the adrenal gland to make too many hormones catecholamines. Drugs that may increase plasma renin activity levels include [ 26 , 27 , 28 ]:.
0コメント