Cortisol and Adrenal
Looks at how your adrenal glands are making their stress and blood pressure hormones, and tests your thyroid too.
Cortisol by itself is hard to read. It is highest in the first hours after waking and falls through the day, so this draw has to happen between seven and nine in the morning, and even then a single level cannot say whether the adrenals are the problem or the pituitary that drives them. ACTH settles that. High ACTH with low cortisol points to the adrenals, and low ACTH with low cortisol points upstream. Aldosterone is the adrenal hormone that controls sodium, potassium and blood volume, and an excess of it is the most common treatable cause of high blood pressure that does not respond to the usual drugs. 17-hydroxyprogesterone is a cortisol precursor that builds up in a mild, late-presenting enzyme defect that shows up as acne, unwanted hair or irregular periods and is routinely mistaken for PCOS. TSH, free T4 and free T3 ride along because thyroid and adrenal symptoms overlap almost completely and the two are often off together. Book the earliest slot you can, and note any steroid use, including inhalers and prednisone courses, because it suppresses the whole axis.
Blood is drawn at a Quest Diagnostics, Labcorp or BioReference patient service center. Price by laboratory: Quest Diagnostics $99, Labcorp $270 or BioReference $224. Your price depends on your state and the laboratories near you. Enter your ZIP code to see them.
What’s included
- Cortisol, morning: Cortisol, a hormone made by the adrenal glands, in a sample drawn between 7 and 9 a.m.
- Adrenocorticotropic hormone (ACTH): Adrenocorticotropic hormone (ACTH), the pituitary hormone that signals the adrenal glands to make cortisol.
- 17-Hydroxyprogesterone (17-OHP): 17-hydroxyprogesterone, a hormone made by the adrenal glands and the ovaries or testes, and a building block for cortisol.
- TSH: Thyroid-stimulating hormone, the pituitary hormone that signals the thyroid.
- Free T3: Free (unbound) triiodothyronine, the active form of thyroid hormone.
- Free T4: Free (unbound) thyroxine, the main hormone the thyroid releases.
- Aldosterone: Measures the level of aldosterone—an adrenal gland hormone that regulates blood pressure, sodium, and potassium—using high-precision
Tests you can add
- C-reactive protein, high-sensitivity (hs-CRP): C-reactive protein, a protein the liver releases during inflammation, measured with a high-sensitivity method.
- Insulin: Insulin, the hormone that signals cells to take up glucose from the blood.
- Vitamin D (25-hydroxy): 25-hydroxyvitamin D, the main form of vitamin D circulating in the blood.
Before your draw
No fasting needed.
Book a morning appointment, ideally between 7 and 9 a.m., for the morning cortisol test. Don't stop your usual medicines unless your clinician tells you to. If you take biotin (vitamin B7), including in hair, skin and nail supplements or multivitamins, have your blood drawn at least 8 hours after a usual dose, or at least 72 hours after a high dose. If biotin was prescribed, ask your clinician before stopping it.