Summary & Overview
HCPCS A9558: Xenon Xe-133 Gas for Diagnostic Ventilation Imaging
HCPCS Level II code A9558 designates xenon xe-133 gas supplied for diagnostic use, measured per 10 millicuries. Xenon-133 ventilation imaging is an established nuclear medicine technique for assessing regional lung ventilation and is used alongside perfusion studies to evaluate pulmonary embolism, ventilation-perfusion mismatch, and other respiratory conditions. The availability and appropriate billing of radiopharmaceuticals like A9558 influence hospital and imaging center workflows, inventory management, and claim processing nationally.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise synthesis of clinical context for ventilation imaging with xenon-133, typical service settings where A9558 is billed, and which payer categories are commonly relevant for coverage considerations. The publication will also summarize benchmarking elements typically examined for radiopharmaceutical billing, note common modifiers used with supply items, and identify areas where input data is not available. This overview is intended to inform revenue cycle, clinical imaging leadership, and policy stakeholders about the role of A9558 in diagnostic nuclear medicine at a national level.
Billing Code Overview
HCPCS Level II code A9558 describes xenon xe-133 gas, diagnostic, per 10 millicuries. This item represents a radiopharmaceutical gas product used for diagnostic nuclear medicine ventilation studies.
Service Type: Diagnostic radiopharmaceutical administration for pulmonary ventilation imaging
Typical Site of Service: Hospital outpatient radiology/nuclear medicine department, imaging centers, and hospital inpatient nuclear medicine units
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult referred to nuclear medicine for a quantitative ventilation study using xenon-133 gas to evaluate regional pulmonary ventilation in the setting of suspected pulmonary embolism, chronic obstructive pulmonary disease, or preoperative pulmonary function assessment prior to lung resection. The patient arrives to the outpatient nuclear medicine suite or hospital imaging department. A technologist confirms identity, indications, allergies, and pregnancy status. The patient is positioned supine on the gamma camera; a closed-circuit breathing apparatus or rebreathing system is placed to administer Xenon Xe-133 gas. Serial ventilation images are acquired while the patient breathes the tracer per protocol. Images are reviewed by the nuclear medicine physician for ventilation distribution, wash-in/wash-out dynamics, and correlation with any concurrently obtained perfusion images. The report documents the administered activity in millicuries (per A9558 units per 10 millicuries), imaging technique, findings, and interpretation. Typical sites of service include the hospital nuclear medicine department, outpatient imaging center, or freestanding ambulatory imaging facility.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier | Standard reporting when no modifier applies |