Summary & Overview
CPT 80400: ACTH Stimulation Test for Adrenal Function
CPT code 80400 denotes the ACTH stimulation test, a key diagnostic procedure used by endocrinologists to evaluate adrenal gland function by measuring cortisol response to synthetic adrenocorticotropic hormone. Nationally, this test matters for accurate diagnosis of adrenal insufficiency and related endocrine disorders, impacting treatment decisions and follow-up care.
Key payers referenced in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication summarizes clinical context, common sites of service, and payer coverage considerations where available. Readers will find succinct benchmarks and service descriptions, clinical indications for ordering an ACTH stimulation test, and a summary of relevant billing and coding considerations tied to this CPT code. Where payer-specific coverage details are not available, the text notes that the input did not include those data.
This resource is intended to provide clinicians, billing professionals, and policy analysts with a concise national overview of CPT code 80400, its clinical role, typical service settings, and what to expect when documenting and reporting this endocrine diagnostic test.
Billing Code Overview
CPT code 80400 describes an ACTH stimulation test, a diagnostic procedure used to evaluate adrenal gland function by measuring cortisol response after administration of synthetic adrenocorticotropic hormone (ACTH). This test is typically ordered and interpreted by endocrinologists to assess the adrenal stress response and help diagnose conditions such as adrenal insufficiency.
Service Type: Diagnostic endocrine testing
Typical Site of Service: Outpatient clinic, endocrinology clinic, or hospital outpatient laboratory
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Clinical & Coding Specifications
Clinical Context
A typical patient is a 45-year-old female referred to endocrinology for evaluation of suspected primary or secondary adrenal insufficiency after episodes of unexplained fatigue, hypotension, weight loss, and persistent hyponatremia. The endocrinologist reviews history, medications (including chronic corticosteroid use or recent steroid withdrawal), and orders an ACTH stimulation test (80400) to assess adrenal cortisol reserve. The patient arrives fasting in the outpatient infusion or procedure area. Baseline blood is drawn for serum cortisol (and often plasma ACTH). Synthetic adrenocorticotropic hormone (cosyntropin) is administered intravenously or intramuscularly per protocol. Timed post‑dose blood samples are taken at specified intervals (commonly 30 and 60 minutes) to measure stimulated serum cortisol. The clinician interprets results in the context of baseline ACTH and clinical presentation to differentiate primary from secondary/tertiary adrenal insufficiency and to guide further management, which may include dynamic endocrine testing, imaging, or adjustment of glucocorticoid therapy. Typical sites of service include outpatient hospital outpatient departments, ambulatory infusion centers, endocrine clinic procedure rooms, and inpatient wards when assessing critically ill patients.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the physician’s interpretation for the test if the facility bills separately for the technical component. |