From the Guidelines
Normal morning cortisol levels for hospitalized patients are generally considered to be between 5 to 25 μg/dL (138-690 nmol/L) when measured between 6-8 AM. However, it's crucial to interpret these levels with caution due to the various factors that can influence cortisol levels in a hospital setting, such as the body's stress response to acute illness, which can elevate cortisol levels to 25-35 μg/dL or higher 1. Medications like exogenous glucocorticoids, estrogens, phenytoin, and rifampin can also impact cortisol production and measurement accuracy. The timing of the blood sample is vital, as cortisol levels follow a diurnal rhythm, peaking in the early morning and decreasing to their lowest levels around midnight.
For an accurate assessment, it is recommended that blood samples be drawn between 6-8 AM, after the patient has been awake for at least one hour. If there is a suspicion of adrenal insufficiency despite normal morning cortisol levels, additional testing such as ACTH stimulation tests may be necessary, as single cortisol measurements can sometimes fail to detect subtle adrenal dysfunction. The high-dose (250-μg) ACTH stimulation test is considered superior for diagnosing primary adrenal insufficiency, with peak cortisol levels below 18 μg/dL indicating adrenal insufficiency 1.
Key considerations for interpreting cortisol levels in hospitalized patients include:
- The impact of the body's stress response to illness on cortisol levels
- The effects of medications on cortisol production and measurement
- The importance of timing in blood sample collection for cortisol testing
- The potential need for additional testing if adrenal insufficiency is suspected despite normal cortisol levels.
From the Research
Normal Morning Cortisol Levels in Hospitalized Patients
The normal morning cortisol level for a hospitalized patient can vary depending on the individual's condition and the reference range used by the laboratory.
- According to the provided studies, there is no direct information on the normal morning cortisol levels for hospitalized patients in general 2, 3, 4, 5, 6.
- However, the studies do provide information on cortisol levels in patients with Cushing's syndrome and adrenal insufficiency. For example, a study published in 2022 reported a morning serum cortisol level of 13 μg/dL in a patient with adrenal Cushing's syndrome 3.
- Another study published in 2021 reported that hair cortisol and cortisone measurements can be used to diagnose overt and mild Cushing's syndrome, but did not provide information on normal morning cortisol levels in hospitalized patients 5.
- A study published in 2009 discussed the utility of salivary cortisol measurements in Cushing's syndrome and adrenal insufficiency, but did not provide information on normal morning cortisol levels in hospitalized patients 6.
Cortisol Levels in Specific Conditions
- In patients with Cushing's syndrome, morning cortisol levels can be elevated, with one study reporting a level of 13 μg/dL 3.
- In patients with adrenal insufficiency, morning cortisol levels can be decreased, with one study reporting a level of 5.1 μg/dL 3.
- It is essential to note that cortisol levels can vary depending on the individual's condition, the time of day, and the reference range used by the laboratory.
Laboratory Reference Ranges
- The reference ranges for cortisol levels can vary depending on the laboratory and the assay used.
- It is crucial to consult the laboratory reference range for cortisol levels to interpret the results accurately.
- The studies provided do not report the normal morning cortisol levels for hospitalized patients, and more research is needed to determine the reference range for this population 2, 3, 4, 5, 6.