1. Introduction to Cortisol

What is Cortisol? Cortisol is a glucocorticoid hormone produced by the adrenal glands, playing a critical role in the body's response to stress, regulation of metabolism, and modulation of the immune system. It follows a diurnal rhythm, with levels peaking in the early morning and declining throughout the day. Measuring serum or salivary cortisol levels is used to diagnose disorders of the hypothalamic-pituitary-adrenal (HPA) axis, such as Cushing’s syndrome, Addison’s disease, or adrenal insufficiency, and to assess stress-related conditions.

2. What is a Cortisol Unit Converter?

Definition: The Cortisol Unit Converter converts cortisol concentrations between various units, enabling standardization of laboratory results for clinical use.

Purpose: It assists clinicians and researchers in interpreting cortisol levels across different measurement units (e.g., nmol/L to µg/dL), ensuring accurate diagnosis and monitoring of adrenal and stress-related disorders.

3. Importance of Cortisol Unit Conversions

Converting cortisol concentrations between units is critical for:

• Standardizing Results: Different labs report cortisol in various units (e.g., nmol/L, µg/dL); conversion ensures consistency for diagnosis and treatment planning.
• Clinical Diagnosis: Accurate conversions aid in diagnosing Cushing’s syndrome, Addison’s disease, and adrenal insufficiency, and in monitoring stress or metabolic disorders.
• Research and Collaboration: Enables comparison of cortisol data across studies or institutions using different measurement standards.

4. Clinical Significance

Elevated Levels (Hypercortisolism): High cortisol levels (e.g., >620 nmol/L or >22 µg/dL in the morning) may indicate:

• Cushing’s syndrome (e.g., due to adrenal tumors, pituitary adenomas, or ectopic ACTH production).
• Chronic stress or depression.
• Exogenous corticosteroid use or severe illness (e.g., critical care settings).

Hypercortisolism can lead to symptoms like weight gain, hypertension, and osteoporosis.

Low Levels (Hypocortisolism): Low cortisol levels (e.g., <140 nmol/L or <5 µg/dL in the morning) may indicate:

• Addison’s disease (primary adrenal insufficiency).
• Secondary adrenal insufficiency (e.g., pituitary dysfunction).
• Suppression from long-term corticosteroid therapy.

Hypocortisolism can cause fatigue, hypotension, and electrolyte imbalances.

Normal Ranges:

• Morning (8 AM): Typically 140–620 nmol/L (5–22 µg/dL).
• Evening (4–8 PM): Typically 55–275 nmol/L (2–10 µg/dL).
• Values vary by lab, time of day, and assay—consult a healthcare provider for interpretation.

5. Precautions

Interferences:

• Cortisol levels follow a diurnal rhythm and are influenced by stress, sleep patterns, medications (e.g., corticosteroids, oral contraceptives), and pregnancy; timed samples (e.g., 8 AM or 4 PM) are critical for accurate interpretation.
• Sample handling (e.g., proper storage, avoiding hemolysis) is essential to prevent degradation of cortisol.
• Interpret cortisol levels with ACTH, dexamethasone suppression tests, clinical symptoms, and patient history—consult a healthcare provider for accuracy.

6. Frequently Asked Questions (FAQ)

Q: Why are there different units for cortisol?
A: Different units reflect varying standards; nmol/L is the SI unit, while µg/dL is commonly used in clinical practice, particularly in regions like the United States.

Q: What is a normal cortisol level?
A: Normal serum cortisol is typically 140–620 nmol/L (5–22 µg/dL) in the morning and 55–275 nmol/L (2–10 µg/dL) in the evening, varying by time of day. Consult a healthcare provider for interpretation.

Q: Can this converter be used for other adrenal hormones?
A: No, this converter is specific to cortisol; other adrenal hormones (e.g., ACTH, DHEA-S) have different molecular weights and conversion factors—consult a healthcare provider for accuracy.