From the Guidelines
To monitor adrenal insufficiency, the primary laboratory tests include morning serum cortisol, ACTH levels, and the ACTH stimulation test, with a standard dose ACTH stimulation test considered for indeterminate results 1. When evaluating patients for adrenal insufficiency, it is essential to assess morning levels of ACTH and cortisol, as well as basic metabolic panels, including sodium, potassium, CO2, and glucose levels 1.
Key Laboratory Tests
- Morning serum cortisol: levels below 5 mcg/dL strongly suggest adrenal insufficiency, while levels above 15 mcg/dL typically rule it out
- ACTH levels: elevated levels with low cortisol indicate primary adrenal insufficiency, while low or normal ACTH with low cortisol suggests secondary insufficiency
- ACTH stimulation test: measures cortisol response before and 30-60 minutes after synthetic ACTH administration, with a normal response showing cortisol rising above 18-20 mcg/dL
- Additional tests: electrolytes, blood glucose, and renin/aldosterone levels in primary insufficiency
Diagnostic Approach
The diagnostic work-up for suspected adrenal insufficiency should include evaluating ACTH and cortisol levels, as well as basic metabolic panels 1. If primary adrenal insufficiency is suspected, further evaluation should include assessing for precipitating causes of crisis, such as infection, and performing an adrenal CT to rule out metastasis or hemorrhage 1. For patients on glucocorticoid replacement therapy, clinical assessment of symptoms is more valuable than laboratory monitoring, with replacement doses typically adjusted based on clinical response rather than cortisol levels 1. Regular monitoring should occur at least annually, with more frequent testing during illness or stress when dose adjustments may be necessary.
From the FDA Drug Label
Patients should be monitored regularly for blood pressure determinations and serum electrolyte determinations (see WARNINGS). The answer to the question of labs to check for monitoring adrenal insufficiency is:
- Blood pressure determinations
- Serum electrolyte determinations 2
From the Research
Labs to Check for Monitoring Adrenal Insufficiency
To monitor adrenal insufficiency, several lab tests can be utilized, including:
- Morning serum cortisol level: This test can be used as a first-step diagnostic test in patients with clinically suspected adrenal insufficiency 3
- Adrenocorticotropic hormone (ACTH) stimulation test: This test is commonly used to diagnose adrenal insufficiency, particularly in critically ill patients 4
- Cosyntropin stimulation test: This test requires method- and assay-specific cutoffs of the level of cortisol, and new diagnostic cutoffs have been established for the Abbott Architect immunoassay 5
Diagnostic Cutoffs
Diagnostic cutoffs for adrenal insufficiency vary depending on the assay used, including:
- A morning cortisol level of >236 nmol/l to predict adrenal sufficiency with sensitivity 84% and specificity 71% 6
- A basal cortisol cut-off of >375 nmol/l to increase specificity to 95% 6
- A cortisol level of 14.6 μg/dL at 60 minutes after ACTH stimulation for the Abbott Architect immunoassay 5
- A cortisol level of 13.2 μg/dL at 30 minutes after ACTH stimulation for the Abbott Architect immunoassay 5
Additional Tests
Additional tests that may be used to monitor adrenal insufficiency include: