Episode 4: The Diagnostic Landscape: Cortisol Testing in Focus
A panelist discusses how screening for excess cortisol in individuals with poorly controlled type 2 diabetes can uncover a hidden hormonal driver of insulin resistance and poor glycemic control, enabling earlier intervention and more targeted, effective treatment to reduce long-term complications.
By
Pamela Kushner, MD
| Published on June 4, 2025
2 min read
The following is an AI-generated summary based on the video content above:
To diagnose cortisol excess, several diagnostic tests are commonly used, including the dexamethasone suppression test, late-night salivary cortisol test, and urinary free cortisol test. These tests assess how cortisol levels are suppressed or measured at different times of day, providing a snapshot of how the body’s circadian rhythm may be disrupted. The diagnosis is typically confirmed when at least 2 first-line tests return unequivocally abnormal results. However, these tests have strengths and limitations that clinicians must consider.
The late-night salivary cortisol and urinary free cortisol tests are particularly helpful in detecting hypercortisolism when the results are abnormally high, strongly suggesting the presence of cortisol excess. However, these tests may not be sensitive enough for milder cases, and false-negative results can occur, necessitating further testing. Moreover, it is important to keep a high index of suspicion before conducting these tests, as negative results do not always rule out the condition. For example, autonomous adrenal tumors may cause intermittent cortisol secretion, which might not be captured by a single late-night salivary cortisol test.
Clinicians must be mindful of factors that could cause false-positive results in these tests, such as dental flossing, brushing teeth too aggressively, eating licorice, smoking, steroid use, or having an abnormal circadian rhythm (eg, shift work). The urinary free cortisol test is particularly prone to inaccuracy in cases of chronic kidney disease, as kidney function can affect the measurement of cortisol excretion. Therefore, a thorough understanding of the tests’ limitations and appropriate patient factors is crucial for accurate diagnosis and treatment of cortisol excess.
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