Summary & Overview
HCPCS Level II M1477: Diagnosis of Delirium
HCPCS Level II code M1477 denotes the diagnosis of delirium and is used to document clinical identification of this acute neuropsychiatric condition during patient encounters. Nationally, accurate coding of delirium supports clinical communication, care coordination, quality measurement, and appropriate billing for services linked to acute cognitive disturbances. Delirium detection and documentation are increasingly relevant given aging populations and cross-setting care transitions.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of the clinical context for M1477, benchmarks and utilization patterns where available, and policy considerations that affect coverage and documentation. The publication outlines how this code is applied across typical sites of service—acute care, emergency departments, and inpatient wards—and summarizes implications for coding workflow, clinical documentation, and payment processes.
This summary provides national-level context rather than jurisdiction-specific guidance. Data not available in the input where payer-specific rates, modifiers, taxonomies, ICD-10 mappings, and related codes would otherwise be presented.
Billing Code Overview
HCPCS Level II code M1477 denotes Diagnosis of delirium. This code represents clinical assessment and identification of delirium as a medical condition, typically used to document that a patient has been diagnosed with delirium during an encounter.
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Service type: Clinical diagnostic evaluation for delirium
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Typical site of service: Acute care settings such as hospitals, emergency departments, and inpatient units, as well as other clinical environments where delirium is diagnosed
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Clinical & Coding Specifications
Clinical Context
A 78-year-old male resident of a skilled nursing facility is observed to have acute onset of confusion, fluctuating attention, disorganized thinking, and altered level of consciousness following a urinary tract infection. Nursing staff notify the facility clinician, who performs an urgent bedside assessment focusing on cognition, orientation, vital signs, oxygenation, medication review, and potential reversible contributors (infection, hypoxia, metabolic disturbance, medication effects). A formal diagnosis of delirium is documented using standard clinical criteria after brief cognitive testing (e.g., CAM — Confusion Assessment Method), review of baseline cognitive status, and targeted history from caregivers. The clinician documents onset, course, precipitating factors, and management plan. Typical workflow includes initial evaluation in the nursing facility or emergency department, orders for labs and imaging as indicated, medication reconciliation, and communication with the primary care provider and family. Typical site of service is inpatient hospital, emergency department, observation unit, or skilled nursing facility when delirium is identified and treated.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
25 | Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure or other service | Use when an E/M visit for delirium evaluation is distinct from another same-day procedure or service |