HCPCS Code J1745: Infliximab billing, units, and modifiers

Key Takeaways

HCPCS Code J1745 describes injection, infliximab, excludes biosimilar, 10 mg – the code for Remicade (Janssen) administered by infusion.

Bill in 10 mg increments: a 200 mg dose requires 20 units (J1745 x 20). Vials are 100 mg each, so wastage must be tracked and reported.

The JW modifier captures discarded drug from single-dose vials, the JZ modifier attests that zero drug was wasted, and the EJ modifier applies to subsequent claims in a defined course of infliximab therapy.

Biosimilar products (Inflectra, Renflexis, Avsola) are billed under separate Q-codes, not J1745. Mixing them up triggers claim denials and compliance flags.

HCPCS Code J1745 is the billing code for injection of infliximab, excluding biosimilars, in 10 mg increments, covering the reference brand Remicade. It is often searched as the J1745 CPT code, though it is technically a HCPCS Level II code maintained by CMS.

HCPCS Code J1745: Definition, clinical context, and code properties

HCPCS Code J1745 describes the injection of infliximab, excluding biosimilar, in 10 mg increments. According to the CMS HCPCS Level II program, J1745 falls under the drug administration category for medications given other than by oral method. The code’s full descriptor reads: “Injection, infliximab, excludes biosimilar, 10 mg.” Some payer systems list it as procedure code J1745.

What infliximab treats and who bills J1745

Infliximab is a chimeric monoclonal antibody that blocks tumor necrosis factor-alpha (TNF-alpha), a cytokine involved in systemic inflammatory conditions. Remicade, marketed by Janssen (Johnson & Johnson), is the branded reference product that providers bill under J1745.

Overall, the FDA has approved infliximab for six conditions: rheumatoid arthritis (RA), Crohn’s disease, ulcerative colitis, ankylosing spondylitis, psoriatic arthritis, and plaque psoriasis. Rheumatology, gastroenterology, and infusion clinic providers are the most common billers.

Remicade is supplied as 100 mg of lyophilized infliximab per 20 mL vial. Because manufacturers dispense the drug in 100 mg containers but you bill it in 10 mg units, you need accurate unit calculation for clean claims.

For example, other HCPCS J-codes for injectable drugs, such as J1815, follow this same per-unit billing structure, though the unit size and mg-per-unit conversion differ by product.

J1745 unit calculation and dosage billing for infliximab infusions

The most common J1745 billing error is submitting the wrong unit count. Because J1745 is defined per 10 mg, the number of units billed must equal the total milligrams administered divided by 10. Enter that unit count in Item 24G of the CMS-1500 claim form, or its electronic equivalent, rounded up to whole units.

Standard dosing example: A patient with rheumatoid arthritis receives 200 mg of infliximab. The correct claim is J1745 x 20 (20 x 10 mg = 200 mg). The American College of Rheumatology coding resources and The Rheumatologist coding corner both confirm this as the standard calculation approach.

Infliximab is weight-based for most indications. For RA, CMS guidance specifies a standard dose of 3 mg/kg IV at weeks 0, 2, and 6, then every 8 weeks.

Providers must document the patient’s weight and the dose calculation in the clinical record because payers routinely cross-reference administered milligrams against body weight when reviewing claims. Good patient record documentation that captures weight at each visit protects against post-payment audits.

J1745 modifiers: When and how to apply JW, JZ, and EJ

In practice, a few modifiers matter most for J1745 claims, and getting them right is the difference between clean reimbursement and a denial or audit flag. Modifier 25 also comes into play when an unrelated evaluation and management (E/M) service happens on the same day as the infusion.

JW modifier: Billing discarded drug from single-dose vials

CMS has identified Remicade (J1745) as a HCPCS code with single-dose containers. So when you open a vial but do not give the full contents, you must not pool, reuse, or quietly absorb the unused portion into overhead.

Instead, you bill the discarded amount on a separate claim line using J1745 with the JW modifier, and you document the wastage in milligrams in the medical record.

Example: A patient receives 360 mg of infliximab. The provider opens 4 vials (400 mg total). The correct billing is: J1745 x 36 for the administered dose, plus J1745 x 4 with the JW modifier for the 40 mg discarded.

The JW line must match exactly the underdosing amount documented in the infusion note. Submitting a JW line without matching documentation is a common audit trigger under the CMS Targeted Probe and Educate (TPE) program.

Palmetto GBA (Medicare Administrative Contractor, Jurisdiction M) conducted a pre-payment TPE review for J1745 covering April through June 2024. Inadequate wastage documentation was among the top findings. Other high-cost infused biologics, such as J9312, face similar wastage documentation scrutiny under TPE reviews.

Practices relying on automated billing workflows that link infusion records directly to claim generation reduce the risk of JW line omissions or mismatches.

JZ modifier: Attesting zero discarded drug

The JZ modifier is the counterpart to JW. Since July 1, 2023, CMS has required the JZ modifier on J1745 claims billed from single-dose vials when no drug is discarded. It attests that the full vial contents reached the patient and nothing was wasted.

A claim from a single-dose container should carry either JW with a matching wastage line, or JZ, but never neither. Payers increasingly edit for the presence of one of the two, so leaving both off is a common denial trigger.

EJ modifier: Subsequent claims in a defined course of therapy

The EJ modifier flags that a drug claim is for a subsequent infusion within a defined course of therapy. For infliximab, a course of therapy means the full induction and maintenance sequence. Add EJ to J1745 on every claim after the initial infusion.

However, the first claim in the series does not carry EJ. As confirmed by The Rheumatologist coding corner, EJ applies to infliximab alongside other defined-course drugs such as erythropoietin and sodium hyaluronate.

J1745 vs biosimilar Q-codes: Choosing the correct code

HCPCS Code J1745 is explicitly restricted to the reference product infliximab (Remicade). Biosimilar versions of infliximab have their own separate codes, and billing a biosimilar product under J1745 is a coding error that most payers will flag on claim edit review. Using the wrong code can result in a denial, a refund demand, or a compliance finding.

Q5109 (Ixifi) was deleted effective December 31, 2025. It is not a valid code for 2026 dates of service and should not be billed going forward.

Payer preferred-product policies for J1745

Payer preferred-product policies are shifting. According to a Point32Health provider bulletin, Remicade (J1745) became a non-preferred product for Harvard Pilgrim Health Care Commercial, Tufts Health Plan Commercial, and Tufts Health Direct members effective January 1, 2026. Avsola (Q5121) and Inflectra (Q5103) became the preferred options instead.

As a result, providers administering Remicade to members of plans with similar policies may face denials or need prior authorization. Always verify preferred status before the infusion date.

Biosimilar interchangeability designations from the FDA may also affect dispensing. As of the current code year, automatic substitution rights vary by biosimilar product and state law.

Do not assume a biosimilar can be substituted for Remicade without checking the FDA interchangeability status and your state pharmacy law. The inventory management system your practice uses should track each product’s HCPCS code separately so the right code always maps to the right drug in the dispensing record.

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J1745 Medicare reimbursement, coverage, and payer policies

Medicare covers infliximab infusions for approved indications when clinical criteria and documentation requirements are met. Reimbursement follows the ASP (Average Sales Price) method for Part B drugs, with payment typically at ASP plus 6%.

Because ASP changes quarterly, the Medicare payment rate for J1745 shifts across the year. Use the CMS fee schedule tool to confirm the current payment amount for your MAC jurisdiction before projecting infusion revenue.

By contrast, hospital outpatient departments bill under OPPS (Outpatient Prospective Payment System), which calculates reimbursement differently from physician office billing under the Medicare Physician Fee Schedule.

Office-based infusion practices billing routine administration under CPT 96365, free-standing infusion centers, and home infusion providers billing under S9379 or CPT 99601 should each confirm their provider type and billing pathway before assuming a single national rate applies.

Prior authorization and medical necessity requirements

Most commercial payers require prior authorization for J1745. Common documentation requirements include:

• The patient’s confirmed diagnosis (ICD-10 code)
• Evidence of failure or contraindication to first-line treatments, typically disease-modifying antirheumatic drugs or corticosteroids for RA
• The prescribing provider’s specialty credentials

Prior authorization requirements vary by payer and plan year, so check the specific payer policy for each patient at each authorization renewal. Many commercial plans also apply step therapy, requiring a preferred biosimilar before they approve Remicade under J1745.

Some state Medicaid programs impose extra restrictions. Louisiana Medicaid, for instance, applies per-diagnosis and per-age-band unit caps on J1745 for provider types outside home infusion therapy and specialty pharmacy.

Home infusion therapy and specialty pharmacy providers are exempt from those unit caps, according to a Louisiana Department of Health Medicaid bulletin. Providers in states with similar Medicaid restrictions should verify billing eligibility before administering the drug under a Medicaid benefit.

J1745 NDC reporting requirements

Many state Medicaid programs and some commercial payers require providers to report the National Drug Code (NDC) alongside J1745 on the claim. NDC reporting captures the specific product lot administered. When your practice administers Remicade, you must enter the NDC for that specific vial lot in the appropriate claim field.

Practices without a system that captures NDC at the point of dispensing often piece this information together from packing slips after the fact, which introduces errors. Prescription management software that records NDC at administration time keeps this data accurate and accessible at claim submission.

Documentation requirements for J1745 claims

Claim denials for J1745 frequently trace back to missing documentation rather than coding errors. Both CMS and commercial payers expect the infusion record to support every element on the claim. The Palmetto GBA TPE review findings for J1745 underscore how often inadequate documentation drives denials during targeted audits.

Each infusion encounter record should contain all of the following:

• Diagnosis: The confirmed ICD-10-CM code that justifies the infliximab infusion. For rheumatoid arthritis with rheumatoid factor, that is ICD-10-CM M05. Crohn’s disease maps to K50. Ulcerative colitis maps to K51. Ankylosing spondylitis maps to M45. Psoriatic arthropathy maps to L40.5. The diagnosis code must be consistent across the prior authorization, the medical record, and the claim.
• Patient weight and dose calculation: The ordered dose in mg/kg, the patient’s current weight, and the resulting milligram total. This lets payers verify that J1745 units billed match the weight-based dose.
• Vials opened vs administered: The number of vials opened, the amount administered, and the amount discarded. This information supports JW modifier claims and protects against wastage fraud allegations.
• Administration time: Infusion start and stop times, supporting the infusion administration codes billed alongside J1745, including CPT 96413 for the first hour and CPT 96415 for each additional hour.
• Clinician signature and credentials: The ordering provider’s NPI and the administering clinician’s credentials and signature on the infusion note.

In short, digital documentation systems that capture all of these fields in a structured infusion template make audit defense straightforward. Digital forms built around infusion workflows ensure that no required data point is skipped at the time of administration, rather than pieced together when a payer requests records.

Common billing errors and how to avoid them

Most J1745 claim denials fall into five patterns. Recognizing them before submission is far less expensive than appealing a denial or responding to a TPE request. Medically Unlikely Edits (MUEs) also cap the units payable for J1745 on a single date of service, so payers automatically deny a unit count above the MUE limit.

• Wrong unit count: Submitting units based on vials opened rather than milligrams administered. Always divide administered mg by 10 to get the correct J1745 quantity.
• Missing JW or JZ modifier: Opening a single-dose vial but neither billing the discarded amount with JW nor attesting zero waste with JZ. Since July 2023, payers expect one of the two on every single-dose vial claim, and leaving both off invites a compliance finding.
• Biosimilar coded as J1745: Administering Inflectra, Renflexis, or Avsola but billing J1745. Each biosimilar has its own Q-code. The NDC on the claim will flag the mismatch immediately.
• Missing EJ modifier on subsequent claims: Billing the second, third, and ongoing infusion visits without the EJ modifier. Some payers edit for its absence on repeat infliximab claims.
• No prior authorization on file: Proceeding with infusion without a valid prior authorization number. For commercial plans, this is one of the leading causes of J1745 denials regardless of medical necessity.

Preventing J1745 denials before submission

As a result, structured billing workflows and compliance management tools that flag missing modifier conditions or authorization expiry before claim submission address all five error patterns in one place. Proactive claim scrubbing also catches errors that manual review misses, especially in high-volume infusion practices billing multiple infused products such as J2323 and J7120 alongside J1745.

For broader infusion practice operational context, the IV therapy best practices guide covers how efficient documentation and claim workflows connect across the full range of infused medications. Practices managing complex biologics billing alongside other infused therapies also benefit from reviewing how EMR for IV therapy handles multi-drug infusion records.

Conclusion

Ultimately, accurate J1745 billing requires three things to align: the correct unit count derived from administered milligrams, the right modifiers applied in the right sequence, and documentation that substantiates every element of the claim. For practices administering Remicade regularly, claim errors and audit exposure compound quickly when any one of those elements is handled inconsistently.

Pabau’s claims management and digital documentation tools help infusion practices capture administered quantities, wastage, and modifier requirements at the point of care, so claims leave the practice clean. To see how Pabau handles infusion billing workflows, book a demo.

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