What is the clinical significance of measuring cortisol levels?

The measurement of cortisol levels is clinically significant primarily for diagnosing conditions such as Cushing's syndrome and Addison's disease. Cushing's syndrome is characterized by excessive production of cortisol, often due to adrenal tumors or pituitary adenomas, while Addison's disease involves insufficient cortisol production, typically stemming from autoimmune destruction of the adrenal glands or other underlying causes.

Testing cortisol levels can help differentiate between these disorders by assessing the body's hormonal balance and identifying abnormalities that may indicate overproduction or underproduction of cortisol. The timing of cortisol testing is also crucial, as cortisol levels typically fluctuate throughout the day, peaking in the morning and declining in the evening, which is an important aspect in diagnosing these conditions effectively.

In contrast, measuring cortisol levels is not primarily associated with diagnosing hypertension, evaluating thyroid function, or monitoring blood glucose levels, as each of these conditions generally involves different biomarkers and testing protocols. For instance, blood pressure monitoring and thyroid function tests focus on different hormonal pathways altogether, while glucose monitoring revolves around insulin and carbohydrate metabolism rather than cortisol.