What is the normal value for cortisol (Cortisol)

From the Guidelines

The normal value for cortisol is considered to be less than 1.8 μg/dL (50 nmol/L) at 0800 h in the morning after 1 mg dexamethasone given between 2300 h and midnight, as indicated by the most recent guideline update 1. When evaluating cortisol levels, it's essential to consider the timing of the sample collection, as cortisol naturally follows a circadian rhythm.

• Morning cortisol levels typically range from 5-23 micrograms per deciliter (mcg/dL) or 138-635 nanomoles per liter (nmol/L).
• Afternoon levels are normally lower, ranging from 3-16 mcg/dL or 83-441 nmol/L. However, these values can be influenced by various factors such as stress, illness, pregnancy, and certain medications, which can temporarily elevate cortisol levels.
• The dexamethasone suppression test, as described in the guideline update 1, is a useful tool for assessing cortisol production and diagnosing disorders like Cushing's syndrome.
• It's crucial to interpret cortisol results in the context of the individual's clinical presentation and medical history, taking into account potential factors that may affect cortisol levels, such as concomitant medications or underlying medical conditions 1.

From the Research

Normal Cortisol Values

The normal value for cortisol is not explicitly stated in the provided studies. However, the studies do mention the following:

• Severely elevated random serum cortisol is defined as more than 36 μg/dL (1000 nmol/L) at any time 2
• A 24-h urinary free cortisol more than fourfold the upper limit of normal is considered severely elevated 2
• Normal urinary free cortisol levels are not explicitly stated, but a decrease from 1296 +/- 176 to 270 +/- 69 nmol/d is considered a significant reduction in cortisol levels 3

Cortisol Measurement

Cortisol levels can be measured in various ways, including:

• 24-hour urinary free cortisol test 4, 2, 5
• Late-night salivary cortisol test 4
• Plasma cortisol levels 2, 3
• Urinary cortisol levels 3

Hypercortisolism Treatment

Treatment for hypercortisolism depends on the underlying cause, but may include:

• Surgery to remove the source of excess cortisol production 4, 2
• Medications such as adrenal steroidogenesis inhibitors (e.g. metyrapone, ketoconazole, osilodrostat) and glucocorticoid receptor blockers (e.g. mifepristone) 6, 2, 5
• Radiation therapy 4, 2
• Bilateral adrenalectomy 4, 2