Summary & Overview
CPT 80420: Dexamethasone Suppression Panel with Serum and 24-hour Urine Cortisol
CPT code 80420 designates a dexamethasone suppression panel measuring baseline and post-dexamethasone serum cortisol and 24-hour urine free cortisol. This laboratory panel is used nationally to evaluate suspected hypercortisolism and other disorders of cortisol regulation; it informs diagnosis and management decisions across outpatient and hospital-based clinical settings. The code matters because standardized coding supports consistent billing for a multi-sample endocrine test that requires timed specimen collection and laboratory processing.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find clinical context about what the test measures and where it is typically performed, along with practical billing and coding context such as common modifiers and typical sites of service. The publication also outlines benchmarking and reimbursement considerations, payer coverage patterns, and implications for laboratory workflows and documentation. Information provided is national in scope and intended to aid coding professionals, laboratory managers, and clinicians who order or bill for endocrine diagnostic testing.
Billing Code Overview
CPT code 80420 describes a dexamethasone suppression panel in which a lab analyst measures both baseline serum cortisol and 24-hour urine free cortisol, administers dexamethasone, and then obtains a second serum cortisol and 24-hour urine free cortisol sampling. This service is a hormonal laboratory panel used to assess cortisol suppression and evaluate disorders of cortisol regulation.
Service Type: Laboratory diagnostic panel
Typical Site of Service: Clinical laboratory or hospital outpatient laboratory
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult referred by an endocrinologist for evaluation of suspected Cushing syndrome after clinical features such as progressive central obesity, facial rounding, wide purple striae, easy bruising, new-onset glucose intolerance, and resistant hypertension. The clinical workflow begins with counseling the patient about the dexamethasone suppression panel and multi-sample collection requirements. Baseline measurements are obtained: a serum cortisol and a 24‑hour urine free cortisol (UFC). The patient is then given a specified dose of dexamethasone (per protocol) and instructed on timing; a second serum cortisol and a second 24‑hour UFC are collected after dexamethasone suppression. The laboratory analyst performs assays on both baseline and post‑dexamethasone serum and urine samples, documents collection times, and reports results to the ordering clinician. Typical sites of service include an outpatient endocrinology clinic, hospital outpatient laboratory, or reference clinical laboratory that can coordinate timed serum draws and 24‑hour urine collection. The purpose is to assess cortisol suppression to help distinguish endogenous Cushing syndrome from pseudo‑Cushing states or exogenous causes.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
11 | Normal, straightforward service | Use when the laboratory professional's work is routine without unusual circumstances affecting complexity. |