Renin activity in plasma (24-hour urine collection)

Why This Test Matters

Your kidneys produce renin, a hormone that plays a key role in controlling how much fluid stays in your body and how much sodium (salt) your body retains. High or low levels of renin can signal problems with blood pressure or kidney function. This test helps doctors understand how well your kidneys are managing these processes over a full day.

What to Expect Before the Test

You’ll collect your urine for 24 hours, starting right after you wake up and ending right before you wake up the next day. Store the urine in a refrigerator or at room temperature, adding a preservative if instructed. Bring all collected urine to your lab for testing.

What the Test Results Mean

Results help doctors evaluate whether your kidneys are producing enough renin or if there’s an imbalance in your body’s natural blood pressure regulation system. Abnormal results may indicate conditions like kidney disease, certain types of hypertension, or hormonal imbalances.

Common Conditions Tested For

This test is often used to diagnose or monitor conditions such as primary hyperaldosteronism (a hormone disorder affecting blood pressure), kidney disease, or conditions affecting the renin-angiotensin system.