HCPCS J1745: infliximab injection, per 10 mg
J1745 is the HCPCS Level II code for infliximab that is not a biosimilar, counted in units of 10 mg. Each biosimilar has its own Q code, so the code on the claim has to match the product the patient was given.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026In short: J1745 reports reference infliximab, 10 mg per unit. Inflectra, Renflexis and Avsola use Q5103, Q5104 and Q5121, and the subcutaneous product uses J1748. CMS counts infliximab among the drugs given with chemotherapy administration codes, and single-dose vial waste needs JW or JZ.
What does HCPCS J1745 report?
The October 2026 HCPCS file from CMS lists J1745 as "Injection, infliximab, excludes biosimilar, 10 mg". It was added on January 1, 2000 and has no termination date. The CMS record layout defines its pricing indicator, 51, as drugs.
The words "excludes biosimilar" are the whole point of the code. J1745 is for the original reference product only. A biosimilar is a separate product with its own code, and billing J1745 for it puts the wrong product on the claim.
| Item | Value in the CMS files |
|---|---|
| Long descriptor | Injection, infliximab, excludes biosimilar, 10 mg |
| HCPCS coverage code | D, special coverage instructions apply |
| Fee schedule status (RVU26D) | E, excluded from the fee schedule by regulation, no RVUs |
| Dosage in the Part B payment limit file (October 2026) | 10 MG |
| NCCI MUE, practitioner and outpatient hospital tables (Q4 2026) | 150 units, indicator 3 (date of service, clinical) |
| On the CMS JW and JZ code list | Yes |
Which code do you bill for each infliximab product?
Bill the code that matches the exact product on the invoice. The October 2026 HCPCS file carries the codes below, all counted per 10 mg.
| Code | Product as CMS words it | Status in the October 2026 file |
|---|---|---|
| J1745 | Infliximab, excludes biosimilar | Active, added 2000-01-01 |
| Q5103 | Infliximab-dyyb, biosimilar (Inflectra) | Active, added 2018-04-01 |
| Q5104 | Infliximab-abda, biosimilar (Renflexis) | Active, added 2018-04-01 |
| Q5121 | Infliximab-axxq, biosimilar (Avsola) | Active, added 2020-07-01 |
| J1748 | Infliximab-dyyb (Zymfentra) | Active, added 2024-07-01, MUE 12 |
| Q5109 | Infliximab-qbtx, biosimilar (Ixifi) | Termination date 2025-12-31 |
| Q5102 | Infliximab, biosimilar (unspecified) | Termination date 2018-03-31 |
The record layout calls the termination date the last date a code may be used by Medicare providers, so Q5109 and Q5102 are for old dates of service only. J1748 is the product-specific code for Zymfentra and is not on the CMS JW and JZ list, which CMS says is not all-inclusive.
Biosimilars are paid differently. Chapter 17, section 20.1, sets the payment limit for a biosimilar at its ASP plus 6 percent of the lesser of the reference product's WAC or ASP, or 8 percent for a qualifying biosimilar. The October 2026 payment limit file marks Q5103 and Q5104 with "8% of reference add-on applied". The rheumatology billing page covers the wider visit.
How many units do you bill for an infliximab dose?
Chapter 17, section 70, says units are entered in multiples of the dose in the code descriptor and a dose above the descriptor amount is rounded up. For J1745 the unit is 10 mg. A dose that comes to 355 mg is 36 units, and a dose under 10 mg is still 1 unit.
The MUE of 150 counts units, so at 10 mg a unit it is 1,500 mg on one date of service.
Waste changes the lines. Example, with made-up numbers: the dose needs 36 units and the vials opened hold 40 units. Line 1 is J1745 with 36 units and no modifier. Line 2 is J1745 with JW and 4 units. If all 40 units were used, one J1745 line with JZ and 40 units is billed.
Is infliximab administration billed as chemotherapy?
In a physician office, usually yes. Chapter 12, section 30.5 D, says the chemotherapy administration codes apply to monoclonal antibody agents and names infliximab among the drugs commonly placed in that group. The list is not complete, and the MAC can add guidance.
That points the visit to 96413 and its add-ons, not to 96365. Under NCCI chapter XI, practitioners report these services only for office care.
How does a J1745 line sit on the claim?
On a CMS-1500, item 24D holds the HCPCS code and up to four modifiers, and item 24G holds the units. On a UB-04, the drug sits under revenue code 0636 with the HCPCS code in form locator 44 and the units in form locator 46.
Chapter 17, section 70, identifies the drug on A/B MAC claims by HCPCS code. Where an NDC is required for Medicaid rebates, CMS tells you to enter N4, then the 11-digit NDC, then a quantity qualifier such as UN and the quantity, in the shaded line of item 24 or in form locator 43. Check each payer's own NDC rule.
How are infliximab units and modifiers entered?
A drug line carries J1745 in Item 24D with the JW or JZ modifier as needed, and the number of 10 mg units in Item 24G. Item 24E points to the condition treated, such as Crohn disease. On a facility bill, the drug sits under its own revenue code in FL 42 with J1745 in FL 44 and units in FL 46. The administration code is a separate line.
RVU26D gives J1745 status E, an item excluded from the fee schedule by regulation with no RVUs, and the MUE table allows 150 units per date with indicator 3, a prescribing information rationale.
Example: A patient weighing 80 kg gets 5 mg per kg, 400 mg, on 10/17 from four 100 mg vials. The line is J1745 JZ, pointer A (K50.90), 40 units, $4,000.00. A line with 160 units would exceed 150.
What denials follow a J1745 line?
| CARC | RARC | What X12 says, and what to check |
|---|---|---|
| 16 | M119 | The line lacks information. M119 is a missing or invalid NDC. Match the NDC to the product billed. |
| 16 | M53 | M53 is missing or invalid units. Recheck the 10 mg math and any split lines. |
| 4 | The code is inconsistent with the modifier. Check that JW or JZ fits the line. | |
| 197 | Precertification or authorization absent. Match the order to the payer's criteria. | |
| 50 | Not deemed medically necessary. Send the diagnosis, prior therapy and dose support. |
Group codes and appeal steps differ by payer. If these denials keep coming back, our denial management team can work them.
Related codes
- October 2026 alpha-numeric HCPCS file and record layout · CMS
- Physician Fee Schedule relative value files, RVU26D (October 2026) · CMS
- Medicare NCCI Medically Unlikely Edits, practitioner and outpatient hospital tables, effective 10-01-2026 · CMS
- October 2026 Medicare Part B drug payment limit file (ASP pricing files) · CMS
- JW Modifier and JZ Modifier Policy HCPCS codes list · CMS
- Discarded Drugs and Biologicals: JW Modifier and JZ Modifier Policy FAQ · CMS
- Medicare Claims Processing Manual, Chapter 12, section 30.5: chemotherapy administration and nonchemotherapy injections and infusions · CMS
- Medicare Claims Processing Manual, Chapter 17: Drugs and Biologicals (sections 20.1, 40, 70) · CMS
- Medicare Claims Processing Manual, Chapter 25: UB-04 form locators 42 to 46 · CMS
- Medicare Claims Processing Manual, Chapter 26: CMS-1500 items 24A to 24G · CMS
- 2026 NCCI Medicare Policy Manual, Chapter XI, section N: chemotherapy administration · CMS
- X12 claim adjustment reason codes · X12
- X12 remittance advice remark codes · X12
We check every rule, code and deadline against the official source. See our editorial policy.
Common questions
Straight answers from the team that does the work.
Ask a billing lead directly. A 20-minute call, Monday to Friday, 9am to 5pm Eastern.
01How do I bill infliximab and its biosimilars?
Bill the code for the exact product on the invoice: J1745 for the reference product, Q5103 for Inflectra, Q5104 for Renflexis, Q5121 for Avsola, J1748 for Zymfentra. Count units of 10 mg, round up, and add JW or JZ on single-dose vial drugs for Medicare Part B.
02Can I bill J1745 for a biosimilar infliximab?
No. The descriptor says "excludes biosimilar", so J1745 is for the reference product only. A biosimilar has its own Q code in the October 2026 HCPCS file. Billing J1745 for it puts the wrong product on the claim, so match the code to the invoice and the NDC before the claim goes out.
03How many units of J1745 can I bill on one day?
The October 2026 NCCI MUE table lists 150 units for J1745, which is 1,500 mg at 10 mg a unit. The edit uses indicator 3, a date of service edit based on clinical data, so a payer can review a higher count if the record supports it.
04Do I use JW or JZ with J1745?
Yes for Medicare Part B when the drug comes from single-dose containers. J1745 is on the CMS JW and JZ code list. Use JW on a second line for the discarded amount and JZ when nothing was discarded. Packaged hospital drugs and multiple-dose containers are outside the policy.
05Is infliximab billed with 96413 or 96365?
Chapter 12, section 30.5 D, of the Medicare Claims Processing Manual names infliximab among drugs commonly given with chemotherapy administration codes, which points to 96413 and its add-ons. The manual lets the MAC add guidance, so confirm your contractor's policy before choosing.
Infliximab claims denied for product or units?
We check the product code, the 10 mg units and the JW or JZ line before infusion claims go out.