From the Guidelines
The normal level of adrenocorticotropic hormone (ACTH) stimulated morning cortisol is not explicitly stated in the provided evidence, but based on the context, it can be inferred that a morning cortisol level above 5-23 micrograms per deciliter (mcg/dL) or 138-635 nanomoles per liter (nmol/L) may be considered abnormal and warrant further testing, such as ACTH stimulation tests, 24-hour urinary free cortisol, or midnight salivary cortisol, as suggested by 1.
Normal Cortisol Levels
Normal morning cortisol levels typically range between 5-23 micrograms per deciliter (mcg/dL) or 138-635 nanomoles per liter (nmol/L), with values being highest in the early morning, as mentioned in the example answer. This reflects the natural circadian rhythm of cortisol secretion, where levels peak shortly after waking and gradually decline throughout the day.
ACTH Stimulation Test
The ACTH stimulation test is used to assess the function of the adrenal glands and can help diagnose adrenal insufficiency or Cushing's syndrome, as mentioned in 1 and 1. However, the normal level of ACTH-stimulated morning cortisol is not explicitly stated in the provided evidence.
Factors Affecting Cortisol Levels
Factors that can affect morning cortisol levels include stress, sleep patterns, medications (particularly steroids), and the timing of blood collection, as mentioned in the example answer. It is essential to consider these factors when interpreting morning cortisol results.
Diagnostic Approach
If morning cortisol results are abnormal, additional testing such as ACTH stimulation tests, 24-hour urinary free cortisol, or midnight salivary cortisol may be needed for definitive diagnosis, as suggested by 1. The diagnostic approach should be individualized based on the patient's clinical presentation and medical history.
Conclusion Not Provided
As per the instructions, no conclusion section is provided. The answer is based on the strongest and most recent evidence available, which is 1.
From the Research
Normal Levels of Adrenocorticotropic Hormone (ACTH) Stimulated Morning Cortisol
- The normal level of morning cortisol is between 200-650 nmol/L 2
- After ACTH stimulation, the normal peak cortisol level is not explicitly stated in the provided studies, but a study suggests that a mean basal morning serum cortisol of > or = 300 nmol/L excludes the possibility of adrenal insufficiency, and a level of < 110 nmol/L suggests adrenal insufficiency 3
- Another study found that a morning serum cortisol of <275 nmol/L identified subnormal-stimulated cortisol with 96.2% sensitivity 4
- The studies suggest that the normal level of ACTH stimulated morning cortisol can vary depending on the individual, their sex, and pubertal status, with higher levels observed in adults and lower levels in prepubertal children 5
Factors Affecting Morning Cortisol Levels
- Sex and pubertal status can affect morning cortisol levels, with higher levels observed in adults and lower levels in prepubertal children 5
- Morning cortisol levels can be influenced by the time of day, with lower levels observed in the afternoon 4
- The studies suggest that morning cortisol levels can be used as a screening test for adrenal insufficiency, but the results should be interpreted with caution and in conjunction with other tests, such as the short synacthen test 3, 4
Diagnostic Criteria for Adrenal Insufficiency
- A mean basal morning serum cortisol of < 110 nmol/L suggests adrenal insufficiency 3
- A morning serum cortisol of <275 nmol/L identified subnormal-stimulated cortisol with 96.2% sensitivity 4
- The studies suggest that a combination of morning cortisol levels and other tests, such as the short synacthen test, can be used to diagnose adrenal insufficiency 2, 3, 4