Plasma Renin Activity (PRA)

What Does Renin Do in Your Body?

Renin is part of the renin-angiotensin-aldosterone system (RAAS), a natural process that helps maintain blood pressure and fluid balance. When your kidneys detect low blood flow or sodium levels, they release renin. This triggers a chain reaction that increases blood pressure and helps your body retain fluids.

Why Might You Need This Test?

Doctors may order a renin test if you have symptoms like high blood pressure, kidney problems, or conditions such as primary aldosteronism, which can cause excess aldosterone production. It may also be used to diagnose or monitor certain hormonal imbalances or kidney-related disorders.

Common Reasons for Testing

Tests like this are often done when doctors suspect an issue with how your kidneys regulate fluid, sodium, or blood pressure. It can help identify whether your symptoms are due to overactive or underactive renin levels, which could guide treatment plans.

What to Expect Before the Test

You may be asked to avoid certain medications or foods for a few days before the test, depending on your doctor’s instructions. Typically, you’ll have a blood sample drawn in a clinic or lab, and the test is usually done on an empty stomach for accuracy.