J2323 HCPCS code: Injection, natalizumab, 1 mg
J2323 is the HCPCS Level II code for injection, natalizumab, 1 mg. In 2024 Medicare paid an average of $17.43 per service for J2323 across 3,371,659 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 300 per day on outpatient hospital claims. Medicare volume fell 22% from 2022 to 2024 (4,348,126 to 3,371,659 services). In 2024, about 1,243 clinicians billed Medicare for J2323 for 1,501 beneficiaries; New York, Florida, Texas accounted for 26% of services.
Code details
| Field | Value |
|---|---|
| Section | J codes — Drugs administered other than oral method |
| Coverage code | C — Carrier judgment |
| Pricing indicator | 51 — Drug or biological (priced per ASP/average sales price rules) |
| BETOS category | O1E — Other drugs |
| Added | 2008-01-01 |
| Last action effective | 2008-01-01 |
Who bills J2323 (2024)
| Measure | Value |
|---|---|
| Clinicians billing (by place of service) | 1,243 |
| Medicare beneficiaries | 1,501 |
| States with claims | 31 |
| Share of services in top 3 states (New York, Florida, Texas) | 26% |
Counts only. Supplier and clinician names, contact lists and state-by-state detail are in Caduvo.
Medicare utilization for J2323, 2022–2024
| Year | Services | Beneficiaries | Avg. allowed | Avg. paid |
|---|---|---|---|---|
| 2022 | 4,348,126 | 1,985 | $21.81 | $17.40 |
| 2023 | 3,855,601 | 1,786 | $22.13 | $17.62 |
| 2024 | 3,371,659 | 1,501 | $21.89 | $17.43 |
States with the most J2323 services (2024)
| State | Services | Avg. paid |
|---|---|---|
| New York | 331,509 | $16.79 |
| Florida | 302,714 | $17.48 |
| Texas | 227,401 | $17.48 |
| North Carolina | 219,620 | $17.67 |
| California | 219,609 | $17.24 |
NCCI unit limits (MUE)
| Claim type | Max units per day | Rationale |
|---|---|---|
| outpatient hospital claims | 300 | Prescribing Information |
| practitioner claims | 300 | Prescribing Information |
What changed for J2323
- 2008-01-01: J2323 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 J2323?
J2323 is the HCPCS Level II code for injection, natalizumab, 1 mg. Short descriptor: "Natalizumab injection".
How much does Medicare pay for J2323?
In 2024, the average Medicare payment was $17.43 per service (average allowed $21.89).
Does Medicare cover J2323?
Coverage code C — Carrier judgment. Coverage is decided by the Medicare contractor (MAC) case by case.
How many units of J2323 can be billed per day?
300 on outpatient hospital claims; 300 on practitioner claims (NCCI medically unlikely edits).
Related J23 codes
- J2300 — Injection, nalbuphine hydrochloride, per 10 mg
- J2305 — Injection, nitroglycerin, 5 mg
- J2310 — Injection, naloxone hydrochloride, per 1 mg
- J2311 — Injection, naloxone hydrochloride (zimhi), 1 mg
- J2312 — Injection, naloxone hydrochloride, not otherwise specified, 0.01 mg
- J2313 — Injection, naloxone hydrochloride (zimhi), 0.01 mg
- J2315 — Injection, naltrexone, depot form, 1 mg
- J2320 — Injection, nandrolone decanoate, up to 50 mg
- J2325 — Injection, nesiritide, 0.1 mg
- J2326 — Injection, nusinersen, 0.1 mg
- J2327 — Injection, risankizumab-rzaa, intravenous, 1 mg
- J2329 — Injection, ublituximab-xiiy, 1mg
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Next steps
- Run a reimbursement report for a device billed under J2323
- Watch J2323 for fee, coverage and descriptor changes
- Build a full Medicare revenue model for J2323
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.