What are the implications of mildly elevated morning adrenocorticotropic hormone (ACTH) and cortisol levels?

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Last updated: May 20, 2025View editorial policy

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From the Guidelines

Mildly elevated morning cortisol levels should be confirmed with repeat testing, ideally with a 24-hour urine cortisol or late-night salivary cortisol test, as recommended by the most recent guideline update 1. To approach mildly elevated am cortisol, consider the following steps:

  • Confirm the elevation with repeat testing to rule out laboratory error or transient stress-related elevation.
  • Use a 24-hour urine cortisol or late-night salivary cortisol test for confirmation, as these tests have high sensitivity and specificity for diagnosing Cushing's syndrome 1.
  • While waiting for further evaluation, focus on stress reduction techniques like meditation, regular exercise, and adequate sleep to help regulate cortisol levels.
  • Limit caffeine intake to before noon, maintain a balanced diet low in processed foods, and practice good sleep hygiene to support overall hormonal balance.
  • If cortisol elevation is suspected to be stress-related, adaptogenic herbs like ashwagandha (300-500mg daily) may help, though consult your doctor before starting any supplements 1.
  • Persistent elevation requires medical evaluation to rule out conditions like adrenal tumors or pituitary disorders, using tests such as the low-dose dexamethasone suppression test (LDDST) or bilateral inferior petrosal sinus sampling (BIPSS) for ACTH-dependent Cushing's syndrome 1.
  • Cortisol follows a natural daily rhythm, highest in the morning to help you wake up and gradually decreasing throughout the day, so understanding this rhythm is crucial for proper diagnosis and management.
  • Chronic elevation can lead to weight gain, muscle weakness, high blood pressure, and impaired immune function, making proper diagnosis and management important to prevent long-term morbidity and mortality 1. Key diagnostic tests and their cut-offs include:
  • 24-hour urine cortisol: >193 nmol/24 h (>70 μg/m2) 1
  • Late-night salivary cortisol: based on local assay cut-off 1
  • LDDST: >=50 nmol/l (>=1.8 μg/dl) 1
  • BIPSS: central-to-peripheral ACTH ratio >=3 after CRH or desmopressin stimulation 1

From the FDA Drug Label

The pharmacological effect of Metopirone is to reduce cortisol and corticosterone production by inhibiting the 11-beta-hydroxylation reaction in the adrenal cortex.

The FDA drug label does not answer the question about mildly elevated am cortisol.

From the Research

Mildly Elevated AM Cortisol

  • A mildly elevated morning cortisol level can be an indicator of various conditions, including Cushing's syndrome (CS) or adrenal insufficiency (AI) 2, 3.
  • The clinical diagnosis of hyper- and hypocortisolism can be established through laboratory methods such as measurement of "free" cortisol in a 24-hour urine sample or the low-dose dexamethasone suppression test 2.
  • In patients with mildly elevated morning cortisol, further testing such as plasma ACTH measurement, corticotropin-releasing hormone injection test, or high-dose dexamethasone suppression test may be necessary to determine the origin of the condition 2.

Diagnostic Tests

  • The overnight 1 mg dexamethasone suppression test and 24-hour urine free cortisol (UFC) are commonly used screening tests for Cushing's syndrome, with high sensitivity and specificity 3.
  • Morning serum cortisol level can be used as a screening test for adrenal insufficiency, with a cutoff value of 234.2 mmol/L having a sensitivity of 83.3% and specificity of 89.1% 4.
  • However, the predictive value of basal cortisol levels for diagnosing adrenal insufficiency is low, with a positive predictive value of 18.9% and low specificity 5.

Interpretation of Results

  • A morning serum cortisol level <83 nmol/L is diagnostic for central adrenal insufficiency, while a value >414 nmol/L excludes the condition 6.
  • A cutoff value of ≤323.3 nmol/L for morning serum cortisol has a sensitivity of 87.7% and specificity of 46.1% for predicting a deficient response to insulin tolerance test 6.
  • Revising cortisol cutoffs and incorporating symptom-based criteria may improve diagnostic accuracy for adrenal insufficiency 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

SERUM MORNING CORTISOL AS A SCREENING TEST FOR ADRENAL INSUFFICIENCY.

Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists, 2020

Research

Reassessing the Role of Morning Cortisol in Adrenal Insufficiency Diagnosis: Insights from a Multicentric Cohort.

Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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