Which lab test measures the concentration of cortisol in the blood?

The measurement of cortisol concentration in the blood is specifically done through a serum cortisol test. Cortisol is a steroid hormone produced by the adrenal glands, and its levels can fluctuate throughout the day, often peaking in the morning and declining throughout the evening. This test is crucial for assessing adrenal function, diagnosing conditions such as Cushing's syndrome or Addison's disease, and investigating various other health issues related to stress response and metabolism.

The comprehensive metabolic panel evaluates various substances in the blood, including glucose, electrolytes, and proteins, but it does not provide specific information about cortisol levels. The liver function test focuses on assessing the health of the liver through enzymes and proteins but also doesn't measure cortisol. Similarly, the thyroid function test is centered around the evaluation of thyroid hormones and their impact on metabolic rate but does not include cortisol measurement. Hence, the serum cortisol test is the only one specifically designed to gauge cortisol levels in the bloodstream.