Cortisol in Saliva (Free Cortisol)

Why This Test Is Done

Salivary cortisol testing is often used to evaluate conditions related to abnormal cortisol levels, such as Cushing’s syndrome (excess cortisol) or adrenal insufficiency (low cortisol). It may also help diagnose circadian rhythm disorders or stress-related hormonal imbalances. Unlike blood cortisol, which can be affected by stress at the time of testing, saliva cortisol provides a more natural, integrated measure over time.

What to Expect Before the Test

No special preparation is needed. You’ll chew on a cotton swab for a few seconds to collect saliva, which is then sent to the lab. Avoid brushing your teeth or consuming caffeine, alcohol, or tobacco for at least 30 minutes before testing, as these can temporarily alter cortisol levels.

How the Test Works

Saliva is collected in a sterile container, and the cortisol in your saliva is measured using a highly sensitive immunoassay technique. This method detects the free (unbound) cortisol, which is biologically active.

What the Results Mean

Results are typically reported as mass concentration (e.g., nanograms per deciliter). Interpretation depends on timing (e.g., morning vs. evening) and clinical context. Your healthcare provider will compare results to your symptoms and other tests to diagnose conditions like adrenal disorders or stress-related hormone imbalances.