24-Hour Urinary Free Cortisol

Why This Test Matters

Cortisol plays a key role in your body’s response to stress, immune function, and metabolism. If your cortisol levels are too high or too low over time, it can lead to health problems like weight changes, fatigue, or hormonal imbalances. This test helps doctors track long-term cortisol activity in your urine.

What to Expect Before the Test

You’ll collect all your urine for a full 24-hour period (typically from one morning to the next). Drink plenty of fluids to help your kidneys pass urine easily. Store the urine in a refrigerator or freezer if needed, but keep it cold to prevent breakdown of cortisol. Bring all collected urine samples to your lab appointment.

How the Test Works

The test measures cortisol levels in your urine, which reflects how much your body naturally produces over time. Unlike blood tests, this method avoids fluctuations caused by stress or timing. Your doctor may use this test to confirm or rule out conditions like Cushing’s syndrome or Addison’s disease.

Possible Results and Next Steps

Results may be compared to a reference range for healthy adults, but individual results can vary. High cortisol levels might suggest overproduction (e.g., from tumors or excess steroid use), while low levels could indicate adrenal gland issues. Your doctor will discuss findings with you and may recommend further testing or adjustments to treatment.