Common mistakes around Cortisol Test

Common mistakes in cortisol testing revolve around sampling and interpretation. Cortisol follows a strong circadian rhythm: peak in the early morning (7–9 AM) and nadir at night. A single random measurement without time reference is nearly meaningless. Stress, poor sleep, alcohol, caffeine, and medications (e.g., glucocorticoids, oral contraceptives) can skew results. Salivary tests are more sensitive than blood or urine but also more prone to contamination. Many direct-to-consumer tests claim to diagnose 'burnout' or 'adrenal fatigue' – a concept not supported by evidence. The Endocrine Society recommends confirmatory testing (dexamethasone suppression or CRH stimulation) before diagnosing Cushing’s or adrenal insufficiency. Without clinical context, false positives and unnecessary interventions are common. Evidence: practice-based; no direct sources from provided context.