Cortisol Test – Understanding Your Stress Hormone Check

When working with cortisol test, a medical assessment that measures the level of cortisol, the body’s primary stress hormone. Also known as stress hormone test, it helps doctors evaluate adrenal health and diagnose conditions like Cushing’s or Addison’s disease. The test is closely tied to the adrenal gland, the small organs perched on top of the kidneys that secrete cortisol, and often involves an ACTH stimulation test, a follow‑up procedure that checks how well the adrenal gland responds to adrenocorticotropic hormone. In practice, a cortisol test can use blood, saliva, or a 24‑hour urine sample. Blood draws are typically taken in the early morning when cortisol peaks, while a midnight sample captures the low‑point of the daily rhythm. Saliva testing offers a non‑invasive way to track the diurnal curve over several days, and urine collection measures the free cortisol that the body actually uses. Each method has its own attribute‑value pair: sample type (blood, saliva, urine), timing (morning, evening, 24‑hour), and diagnostic purpose (screening for Cushing’s, confirming Addison’s, monitoring therapy). Understanding these attributes helps you and your provider choose the right approach for your situation.

Why the cortisol test matters for stress and metabolism

Cortisol is more than a stress marker; it regulates glucose, blood pressure, immune response, and even sleep cycles. Because the hormone follows a strict diurnal pattern—high in the morning, low at night—any disruption can signal an underlying endocrine issue. Elevated morning levels often point to Cushing’s syndrome, a condition where excess cortisol leads to weight gain, hypertension, and bone loss. Conversely, unusually low levels may indicate Addison’s disease or secondary adrenal insufficiency, both of which can cause fatigue, low blood pressure, and electrolyte imbalances. The test therefore serves as a gateway to diagnosing a range of metabolic disorders. For patients with chronic stress, persistent high cortisol can contribute to insulin resistance and abdominal fat, making the cortisol test a useful snapshot of how the body is handling long‑term pressure. By capturing the hormone’s concentration at key points, clinicians can link the data to lifestyle factors, medication effects, and other lab results such as ACTH levels, providing a holistic view of your endocrine health.

Preparing for a cortisol test is straightforward but important. Most labs ask you to avoid heavy meals, caffeine, and nicotine for at least an hour before a blood draw, because these can cause short‑term spikes. Certain medications—like steroids, oral contraceptives, and some antidepressants—may interfere with results, so a thorough medication review is essential. If you’re scheduled for a saliva series, maintain a consistent sleep schedule and refrain from brushing your teeth or using mouthwash before each sample, as these can dilute the hormone. After the test, your doctor will compare your numbers to reference ranges that account for age, sex, and time of day. When numbers fall outside the range, a follow‑up ACTH stimulation test often follows to pinpoint whether the problem originates in the adrenal gland itself or higher up in the hypothalamic‑pituitary axis. Additional tools like a 24‑hour urine free cortisol test or a dexamethasone suppression test may be ordered to confirm a diagnosis and guide treatment plans.

Below you’ll find articles that dive deeper into specific aspects of cortisol testing—from the genetics of adrenal disorders to practical tips for managing test‑related stress. Whether you’re looking for a quick overview, detailed comparisons of testing methods, or actionable steps to lower chronic cortisol levels, the collection below offers a curated look at everything you need to know about this essential hormone check.