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Recognizing the role of hypercortisolism in managing patients with difficult-to-control type 2 diabetes

Patients with difficult-to-control type 2 diabetes (T2D) are on multiple medications to lower blood glucose and/or blood pressure but still have an HbA1c greater than 7.5%. More than 25% of patients with type 2 diabetes fall into this category.1 Recent research has shown the prevalence of hypercortisolism in patients with difficult-to-control T2D can be as high as 24%.1

In this article:

Clinical challenge | Why it matters | Ordering recommendations | Interpreting test results | Next steps | Supporting resources

 

Clinical challenge: Hypercortisolism is often overlooked as a driver of hyperglycemia 

Hypercortisolism is a condition of high cortisol levels that can negatively impact overall health in several ways, from metabolic complications to increased risk of cardiovascular events.2

Chronically elevated cortisol levels cause insulin resistance, hyperinsulinemia, and glucose intolerance, and disrupt the hypothalamic-pituitary-adrenal (HPA) axis—which can lead to psychiatric, metabolic, and immune disorders.3

While severe cases may present as Cushing syndrome, many patients lack classic symptoms and/or present nonspecific symptoms. This leads to frequent under-recognition and delayed evaluation of hypercortisolism.4,5

Potential symptoms of high cortisol6

  • Weight gain, particularly around the face (moon face) and abdomen
  • Acne
  • Thinning skin
  • Susceptibility to bruising
  • Flushed face
  • Slow healing
  • Muscle weakness
  • Severe fatigue
  • Irritability
  • Difficulty concentrating
  • High blood pressure
  • Headache

For patients with difficult-to-control T2D, underlying conditions such as hypercortisolism may impair glycemic control

While the most severe form of hypercortisolism, overt Cushing syndrome, presents with symptoms including a rounded “moon face,” purple or pink stretch marks (striae) on the abdomen, breasts, and hips, and a hump or fat pad between the shoulders, milder forms with minimal symptoms are now believed to be more common.7,8

 

For that reason, experts suggest testing for hypercortisolism even in the absence of specific signs.8,9

 

Screening for chronically elevated cortisol levels is recommended particularly for patients with difficult-to-control T2D who are taking multiple medications to lower glucose but still have HbA1c greater than 7.5%.4,5

 

Why it matters: Hypercortisolism is associated with significant morbidity and mortality risk10

Chronic elevated cortisol levels can impact nearly every organ system in the body, including cardiovascular, infectious, metabolic, reproductive, dermatologic, neuropsychiatric, and bariatric comorbidities.10

Hypercortisolism is independently associated with cardiovascular disease and the increased mortality seen in individuals with T2D.5

The significant morbidity and mortality risk associated with hypercortisolism10 reinforces the importance of cortisol level screening in primary care settings.

Hypercortisolism may affect a significant subset of T2D patients

Ordering recommendations: Hypercortisolism screening in primary care settings may be appropriate for certain T2D patients

Quest Diagnostics offers several tests for initial evaluation of hypercortisolism.

In primary care, screening for hypercortisolism may be appropriate for patients presenting with these clinical features:

  • Persistent hyperglycemia despite intensified therapy
  • Worsening hypertension or metabolic syndrome
  • Progressive weight gain or central obesity

Clinical guidelines focus on screening for chronic high cortisol levels and Cushing syndrome with high-sensitivity tests including the dexamethasone suppression test (DST), dexamethasone levels, morning cortisol (Cortisol AM), and total cortisol.10

Recommended tests: Dexamethasone, cortisol testing for hypercortisolism

Dexamethasone Suppression Test (DST), 1 specimen

  • Test code: 6921
  • CPT® code: 82533

Clinical use: Diagnosing hypercortisolism

Dexamethasone

  • Test code: 29391
  • CPT® code: 80299*

Clinical use: Aiding the interpretation of DST (test code 6921)

Cortisol, AM

  • Test code: 4212
  • CPT® code: 82533

Clinical use: Evaluating for hypercortisolism

Cortisol, Total

  • Test code: 367
  • CPT® code: 82533

Clinical use: Evaluating for hypercortisolism

* CPT code is subject to a Medicare Limited Coverage Policy and may require a signed ABN when ordering.

Note: The CPT codes provided are based on American Medical Association guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

 

Interpreting test results: Using cortisol test findings to guide further diagnostics and other recommendations

Dexamethasone Suppression Test (DST)

For 1 mg overnight DST, 1 mg dexamethasone administered at 11:00 PM; cortisol measured at 8:00 AM the following day. Normal range is less than 1.8 mcg/dL, indicating suppression. Greater than 1.8 mcg/dL indicates abnormal or no suppression, suggesting hypercortisolism.11

Dexamethasone 

Measured post-DST to verify absorption. Therapeutic levels (around 180-500 ng/dL morning after 1 mg dose) confirm compliance if cortisol is not suppressed. Low levels indicate poor absorption or noncompliance, invalidating abnormal DST results.10

Diagnostic algorithm to evaluate hypercortisolism

Consult the algorithm for the most appropriate testing path for patients suspected to have hypercortisolism.

Cortisol, AM

Typically, cortisol levels are highest early in the morning and lowest at night. The normal morning serum cortisol (6:00-8:00 AM) range is 10-20 mcg/dL.12 Elevated levels greater than 20 mcg/dL suggest possible hypercortisolism but alone are nonspecific, as they can be markers of stress or pseudo-Cushing states. Diurnal rhythm loss (elevated late-night cortisol) is more diagnostic.7

Cortisol, Total

Total serum cortisol measures both free and bound forms, with AM reference range 10-20 mcg/dL and PM reference range 3-10 mcg/dL.12 For hypercortisolism screening, total cortisol is used in conjunction with other tests. Isolated elevations are common in physiologic states and require confirmation with DST or urinary free cortisol.10

 

Next steps: Referral for further diagnostic evaluation and hypercortisolism management

Patients with suspected hypercortisolism should be referred to an endocrinologist for additional evaluation, etiologic determination, and condition management. Treatments do exist to lower cortisol levels and can significantly improve patient outcomes. Additional specialist referrals may be indicated depending on the underlying cause(s) of high cortisol levels.10

 

Supporting resources

Need more information?

Talk to your Quest representative for more information about hypercortisolism screening.

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References

1. American Diabetes Association. One in four patients with difficult-to-control type 2 diabetes experience high levels of cortisol. Published June 24, 2024. Accessed March 24, 2026. https://diabetes.org/newsroom/press-releases/one-four-patients-difficult-control-type-2-diabetes-experience-high-levels

2. Busch B. Understanding the impact of hypercortisolism on health and quality of life. The Educated Patient. Published October 22, 2025. Accessed March 24, 2026. https://www.theeducatedpatient.com/view/understanding-the-impact-of-hypercortisolism-on-health-and-quality-of-life

3. Cleveland Clinic. Hypothalamic-pituitary-adrenal (HPA) axis. Updated April 12, 2024. Accessed March 25, 2026. https://my.clevelandclinic.org/health/body/hypothalamic-pituitary-adrenal-hpa-axis

4. Buse JB, Kahn SE, Aroda VR, et al. Prevalence of hypercortisolism in difficult-to-control type 2 diabetes. Diabetes Care. 2025;48(12):2012-2020. doi:10.2337/dc24-2841

5. Nieman LK, Muniyappa R. Unmasking hypercortisolism in difficult-to-control type 2 diabetes: a useful paradigm shift? Diabetes Care. 2025;48(12):1994-1996. doi:10.2337/dci25-0038

6. Healthline. What are the symptoms and causes of high cortisol levels? Updated March 20, 2025. Accessed March 24, 2026. https://www.healthline.com/health/high-cortisol-symptoms

7. Nieman LK, Biller BMK, Findling JW, et al. The diagnosis of Cushing’s syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008;93(5):1526-1540. doi:10.1210/jc.2008-0125

8. DeFronzo RA, Auchus RJ. Cushing syndrome, hypercortisolism, and glucose homeostasis: a review. Diabetes. 2025;74(12):2168-2178. doi:10.2337/db25-0120

9. Miller BS, Auchus RJ. Evaluation and treatment of patients with hypercortisolism. JAMA Surg. 2020;155(12):1152-1159. doi:10.1001/jamasurg.2020.3280

10. John TA, Anastasopoulou C. (2026). Hypercortisolism (Cushing syndrome). StatPearls.  Updated November 28, 2025. Accessed March 24, 2026. https://www.ncbi.nlm.nih.gov/books/NBK551526/

11. Kalender DSY, Çalan M, Özışık S, et al. Optimizing diagnostic accuracy in Cushing syndrome using 1 MG dexamethasone suppression test cut-offs. Acta Endocrinol (Buchar). 2024;20(4):422-429. doi:10.4183/aeb.2024.422

12. University of Rochester Medical Center. Cortisol (serum). Published 2024. Accessed March 26, 2026. https://www.urmc.rochester.edu/encyclopedia/content?contenttypeid=167&contentid=cortisol_serum