The Serum Cortisol Test (7-9 AM) measures the level of cortisol in the blood, specifically taken in the early morning, typically between 7:00 and 9:00 AM. Cortisol levels are highest in the morning as part of the body’s natural circadian rhythm, helping to regulate metabolism, immune response, and stress. This test is commonly used to assess adrenal function and diagnose conditions like Cushing’s syndrome (excess cortisol) or Addison’s disease (low cortisol). Morning cortisol levels are especially important for evaluating adrenal health, as cortisol typically peaks in the early morning and decreases throughout the day. Abnormal results can indicate hormonal imbalances or adrenal disorders.