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ACTH Unit Converter
Adrenocorticotropic hormone (ACTH), also known as corticotropin, is a polypeptide tropic hormone produced and secreted by the anterior pituitary gland. It is a key component of the hypothalamic-pituitary-adrenal (HPA) axis. Its primary function is to stimulate the adrenal cortex to secrete glucocorticoids, primarily cortisol.[Image of HPA axis regulation]
ACTH secretion follows a distinct circadian rhythm, peaking in the early morning (6:00–8:00 AM) and reaching its nadir around midnight. Measurement of plasma ACTH is essential in the differential diagnosis of Cushing’s syndrome (excess cortisol) and Adrenal Insufficiency (Addison’s disease). Because ACTH is unstable and degrades rapidly, proper sample handling (chilled EDTA tubes) is critical. This converter facilitates accurate interpretation between the standard SI unit (pmol/L) and conventional mass units (pg/mL).
SI Units
RecommendedPicomoles per liter (Standard International).
Conventional Units
Clinical Context
ACTH levels must always be interpreted in conjunction with simultaneous cortisol levels. In primary adrenal insufficiency (Addison’s), cortisol is low while ACTH is elevated due to lack of negative feedback. In secondary adrenal insufficiency (pituitary failure), both ACTH and cortisol are low.
For Cushing’s syndrome, a suppressed ACTH (< 5 pg/mL) suggests an adrenal tumor, whereas elevated or normal levels suggest an ACTH-producing pituitary tumor (Cushing’s disease) or ectopic ACTH production. Therapeutic ranges vary by assay, but typical morning values are 1.6 – 13.9 pmol/L (7.2 – 63 pg/mL).
Clinical References
How to Use This Calculator
Follow these steps to get accurate clinical conversions instantly.
Enter Values
Input your laboratory results into the corresponding unit field (e.g., pg/mL). You can use either dot or comma decimals.
Automatic Conversion
The calculator works in real-time. As you type in one field, all other units (like pmol/L) are instantly updated.
Verify Units
Check the SI Units section for the internationally recommended reporting standard (pmol/L).
Reset
Use the Clear button to reset all fields before starting a new calculation.
Frequently Asked Questions & Tips
The conversion factor is approx. 4.54. Specifically, 1 pmol/L ≈ 4.541 pg/mL, derived from the molecular weight of ACTH (~4541 g/mol).
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