Plasma Renin Activity

Other names: Renin Test, Plasma Renin Activity; Random Plasma Renin; PRA, aldosterone-renin ratio (ARR)

This  test measures the amount of renin in the blood.

Normal range

 1.9 to 3.7 ng/ml/hour.

Requirements

Certain medication, salt intake, pregnancy, stress can affect the results of the test. Kindly, consult your technician or doctor regarding the precautions you need to consider before getting the test done.

When you have high blood pressure (hypertension), it is crucial to find the reason for it in order to manage the condition. Renin is enzyme that is made in kidneys and plays crucial rols in maintaining blood pressure. It maintains this with help of other enzymes known as angiotensin and aldosterone. This whole pathway and balance of blood pressure is known as “ renin-angiotensin” pathway.

When blood pressure drops or goes down, renin is released in blood, which triggers angiotensin and aldosterone. Angiotensin make blood vessels narrow and aldosterone signlas kidneys to retain salt and water, both these action increase the blood pressure. If this balance is disturbed, blood pressure can significantly increase resulting in hypertension.

This is is measured as part of the diagnosis and treatment of hypertension (high blood pressure). Levels of renin and aldosterone are tested at the same time, this is known as plasma renin activity test or an aldosterone-renin ratio. This test is used to diagnose if aldosterone levels in body are normal or not. The test is especially useful in diagnosing primary aldosteronism (PA), a disease that happens from having too much aldosterone. PA, also known as primary hyperaldosteronism or Conn syndrome, causes high blood pressure. If not treated, high blood pressure increases the risk of stroke, heart attack, and kidney failure.

Your doctor will advised you this test if you are diagnosed with hypertension and not responding to standard blood pressure medication. You are also adviced this test if you have symptoms of low potassium like headache, cramps, weakness, excessive thirt etc.

Interpretation

Results higher than normal could mean, addison’s disease, liver cirrhosis or scar or dehydration. While lower results indicate kidney disorders and PA. Most often, your renin test results will be compared with aldosterone test results. Depending on your results, your provider may recommend medicine and/or diet and lifestyle changes to treat your condition.Eg. If renin and aldosterone both are low it could mean body is producing too much cortisol while low renin and high aldosterone indicate PA (adrenal glands to make too much aldosterone)