A9558 HCPCS code: Xenon xe-133 gas, diagnostic, per 10 millicuries
A9558 is the HCPCS Level II code for xenon xe-133 gas, diagnostic, per 10 millicuries. In 2024 Medicare paid an average of $198.55 per service for A9558 across 245 services. Its Medicare coverage code is C (Carrier judgment): Coverage is decided by the Medicare contractor (MAC) case by case. The NCCI unit limit is 7 per day on outpatient hospital claims. Medicare volume fell 4% from 2022 to 2024 (254 to 245 services). In 2024, about 25 clinicians billed Medicare for A9558 for 117 beneficiaries.
Code details
| Field | Value |
|---|---|
| Section | A codes — Transportation, medical/surgical supplies and miscellaneous |
| Coverage code | C — Carrier judgment |
| Pricing indicator | 57 |
| BETOS category | I1E |
| Added | 2006-01-01 |
| Last action effective | 2006-01-01 |
Who bills A9558 (2024)
| Measure | Value |
|---|---|
| Clinicians billing (by place of service) | 25 |
| Medicare beneficiaries | 117 |
| States with claims | 2 |
Counts only. Supplier and clinician names, contact lists and state-by-state detail are in Caduvo.
Medicare utilization for A9558, 2022–2024
| Year | Services | Beneficiaries | Avg. allowed | Avg. paid |
|---|---|---|---|---|
| 2022 | 254 | 124 | $220.18 | $176.13 |
| 2023 | 236 | 115 | $218.22 | $174.91 |
| 2024 | 245 | 117 | $249.04 | $198.55 |
States with the most A9558 services (2024)
| State | Services | Avg. paid |
|---|---|---|
| Florida | 211 | $208.52 |
| Texas | 12 | $149.87 |
NCCI unit limits (MUE)
| Claim type | Max units per day | Rationale |
|---|---|---|
| outpatient hospital claims | 7 | Prescribing Information |
| practitioner claims | 7 | Prescribing Information |
What changed for A9558
- 2006-01-01: A9558 added to HCPCS Level II
- Next scheduled CMS quarterly update (HCPCS and DMEPOS fee schedule): 2027-01-01
Frequently asked questions
What is HCPCS code A9558?
A9558 is the HCPCS Level II code for xenon xe-133 gas, diagnostic, per 10 millicuries. Short descriptor: "Xe133 xenon 10mci".
How much does Medicare pay for A9558?
In 2024, the average Medicare payment was $198.55 per service (average allowed $249.04).
Does Medicare cover A9558?
Coverage code C — Carrier judgment. Coverage is decided by the Medicare contractor (MAC) case by case.
How many units of A9558 can be billed per day?
7 on outpatient hospital claims; 7 on practitioner claims (NCCI medically unlikely edits).
Related A95 codes
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- A9503 — Technetium tc-99m medronate, diagnostic, per study dose, up to 30 millicuries
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Building a device that would bill under a code like this? Caduvo matches a device description to HCPCS/CPT codes, Medicare coverage and payment, and the FDA pathway in one report.
Next steps
- Run a reimbursement report for a device billed under A9558
- Watch A9558 for fee, coverage and descriptor changes
- Build a full Medicare revenue model for A9558
Sources: CMS HCPCS Level II release October 2026; CMS DMEPOS fee schedule; CMS NCCI MUE tables; CMS Medicare utilization (physician and DME supplier files); CMS Medicare Coverage Database articles. Fees are Medicare allowables, not commercial rates. Not billing or legal advice.