What labs to add for adrenal assessment?

From the Guidelines

To assess adrenal function, I recommend ordering the following labs: 1 mg dexamethasone suppression test (DST), aldosterone/renin ratio (ARR), plasma free metanephrines, and DHEAS, as these tests can help identify hormone excess and guide further management. When evaluating patients with suspected adrenal disorders, it is essential to consider the clinical presentation and medical history.

• For patients with hypertension and/or hypokalemia, the aldosterone/renin ratio (ARR) is the preferred initial test to screen for primary aldosteronism 1.
• The 1 mg DST is the preferred screening test for identifying autonomous cortisol secretion when clinically appropriate, with a cutoff value of 50 nmol/L to exclude cortisol hypersecretion 1.
• Plasma free metanephrines can be used to screen for catecholamine excess, particularly in patients with hypertension or other symptoms suggestive of pheochromocytoma 1.
• DHEAS can be used to evaluate androgen excess, particularly in patients with suspected adrenocortical carcinoma or virilization 1. It is crucial to interpret these test results in the context of the patient's clinical presentation and medical history, and to consider additional testing or referral to a specialist as needed. In patients with suspected primary adrenal insufficiency, autoantibody testing, such as 21-hydroxylase autoantibodies (21OH-Ab), and imaging studies, such as CT or MRI of the adrenal glands, may also be necessary 1. Overall, a comprehensive approach to adrenal assessment should include a combination of clinical evaluation, laboratory testing, and imaging studies to guide diagnosis and management.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Adrenal Assessment Labs

To assess adrenal function, several labs can be utilized, including:

• Morning serum cortisol (MSC) level: This is a commonly used screening test for adrenal insufficiency, with a high correlation to peak cortisol response in the ACTH test 2, 3
• Adrenocorticotropic hormone (ACTH) stimulation test: This test is considered the gold standard for assessing adrenal function, but it may not be necessary in all cases, especially if the MSC level is within a certain range 2, 4, 5
• Cosyntropin stimulation test: This is a type of ACTH stimulation test that can be used to assess adrenal function 6, 5
• Dexamethasone suppression test: This test can be used to assess for hypercortisolism (Cushing's syndrome) 6
• 24-hour urine cortisol collection: This test can be used to assess for hypercortisolism (Cushing's syndrome) 6

Specific Lab Values

Certain lab values can be used to predict adrenal insufficiency or sufficiency, including:

• Basal cortisol level: A level of ≥450 nmol/L can rule out adrenal insufficiency, while a level of ≤100 nmol/L can rule in adrenal insufficiency 5
• Morning serum cortisol level: A level of ≥300 nmol/L can exclude the possibility of adrenal insufficiency, while a level of <110 nmol/L can suggest adrenal insufficiency 3
• Peak cortisol response in the ACTH test: A level of <550 nmol/L in the high-dose test or <500 nmol/L in the low-dose test can indicate adrenal insufficiency 5

Lab Selection

The choice of lab test will depend on the clinical suspicion of adrenal insufficiency or hypercortisolism, as well as the patient's symptoms and medical history. In some cases, a single basal cortisol level may be sufficient to rule out adrenal insufficiency, while in other cases, a more comprehensive evaluation, including an ACTH stimulation test, may be necessary 2, 4, 5, 3