HCPCS code J2355: Injection, oprelvekin, 5 mg

Key takeaways

HCPCS code J2355 describes Injection, oprelvekin, 5 mg, a recombinant interleukin-11 used to prevent severe thrombocytopenia following myelosuppressive chemotherapy.

Neumega, the brand of oprelvekin sold in the US, has been discontinued, so confirm the product is available before you bill J2355.

Billing is per 5 mg unit administered, and reporting fewer units than the dose given is the most common error on J2355 claims.

Medicare Part B pays J2355 at ASP plus a percentage add-on, and the rate changes quarterly, so check the current CMS ASP file.

Pabau’s claims management software tracks J-code units, modifiers, and documentation requirements so oncology and infusion practices can submit J2355 claims cleanly the first time.

HCPCS code J2355 is the Level II billing code for Injection, oprelvekin, 5 mg. Oprelvekin is a recombinant form of interleukin-11, a growth factor that stimulates platelet production. It was sold in the US as Neumega, made by Pfizer/Wyeth, and prescribed to prevent severe thrombocytopenia in adults at high risk after myelosuppressive chemotherapy.

The code belongs to the J-code series of HCPCS Level II, which CMS maintains for drugs given by a route other than oral. J-codes are not CPT codes. They appear on CMS-1500 and 837P professional claims, and they pay on ASP-based methodology rather than the physician fee schedule’s relative value units. Sending J2355 down the RVU path is how a claim ends up priced wrong.

For oncology and infusion practices, J2355 is a niche code with high stakes on every line. A single unit error or a missing modifier can produce a denial, or an overpayment recoupment request from a Medicare Administrative Contractor (MAC). Both trace back to the clinical record rather than the claim form, which is why cleaner claims management starts at documentation.

J2355 code details at a glance

The table below summarizes the key descriptor fields coders need before placing J2355 on a claim. These match the official CMS HCPCS code file and are current as of the 2026 code year. Always verify effective and termination dates against the current annual HCPCS release, as CMS can modify or retire codes in any given fiscal year.

A note on drug availability: Neumega (oprelvekin) has been discontinued and is no longer marketed in the US. HCPCS code J2355 itself stays active for 2026, so residual or backorder stock can still be billed against it. Confirm the product is available before you bill, and check whether your MAC has issued a local coverage determination (LCD) for this code. An LCD supersedes general guidance.

Medicare coverage and reimbursement for J2355

Medicare Part B covers injectable drugs furnished incident to a physician’s service when they meet medical necessity criteria. HCPCS code J2355 falls in this category. Oprelvekin is a Part B drug rather than a Part D drug, because it is typically given in an outpatient setting instead of at home.

Before submitting a J2355 claim, verify that the patient’s Part B coverage is active for the date of service. A lapse in Part B enrollment produces a denial that no amount of resubmission will fix.

J2355 fee schedule and ASP-based payment rates

CMS reimburses Part B drugs using Average Sales Price (ASP) methodology. The quarterly CMS Physician Fee Schedule lookup publishes ASP-based payment limits by HCPCS code. For J2355, the allowable is ASP plus a percentage add-on. That add-on is typically 6% for drugs outside the competitive acquisition program, and policy updates can change it.

ASP rates update quarterly, in January, April, July and October. The figure in effect when you submit may differ from the rate at the start of the year. Always pull the current quarter’s CMS ASP drug pricing file before finalizing your expected reimbursement. Billing on a prior quarter’s rate does not protect you from recoupment if an audit finds you were overpaid.

The electronic remittance advice (ERA) is where a J2355 payment gets explained. It shows the allowed amount, the contractual adjustment, and the patient responsibility. If the allowed amount differs from your expected ASP calculation, read the remittance before you call the MAC. The difference is often a quarterly rate change rather than a processing error.

Billing guidelines for J2355

Oprelvekin is dosed at 50 mcg/kg of body weight, given subcutaneously once daily. HCPCS code J2355 is built around a 5 mg unit, so the units billed must match the milligrams administered. A 75 mg dose reports as 15 units. Under-reporting units is a documentation error. Over-reporting them without clinical justification is a compliance risk, and both surface during MAC audits.

Five fields decide whether a J2355 line pays, and each one fails differently. The sections below take them in turn.

Common modifiers used with J2355

Modifiers clarify the circumstances of drug administration and can affect reimbursement or audit outcomes. The most frequently used modifiers with J-codes like J2355 include:

• JA (Administered intravenously): Flags an IV route. Oprelvekin is normally given subcutaneously, so JA rarely applies to J2355
• JB (Administered subcutaneously): The expected modifier here, confirming the route of administration on the claim line
• KD (Drug or biological infused through a DME pump): Not typical for J2355, but it can apply to home infusion
• GY (Item/service not covered): Used to obtain a denial for a secondary payer, or to bill the patient
• GA (Advance Beneficiary Notice on file): Attach when Medicare is expected to deny coverage and the patient has signed an ABN

Always check with your MAC for current modifier guidance. CGS Medicare and Noridian Medicare publish quarterly HCPCS update bulletins that include modifier changes affecting J-code series billing.

Documentation requirements

Medicare requires that the medical record support medical necessity for J2355. At minimum, documentation should include:

• The confirmed diagnosis of chemotherapy-induced thrombocytopenia or high risk of thrombocytopenia following myelosuppressive chemotherapy
• The patient’s weight and the calculated dose in mg or mcg/kg
• The date, route, and site of administration
• The prescribing physician’s order
• The lot number and NDC of the oprelvekin product used (required for the NDC crosswalk on the claim)

Structured intake forms and clinical note templates capture these elements in one workflow. That cuts the back-and-forth when a MAC requests documentation during a post-payment review. The supporting ICD-10-CM diagnosis codes belong in that note as well, since the diagnosis is what carries medical necessity. A complete administration record is the first line of defense in an audit.

Common billing errors on J2355 claims

Most J2355 denials trace back to three specific failure points:

• Incorrect unit count: Billing a flat “1 unit” regardless of the dose administered. J2355 is always billed per 5 mg, so a 50 mg dose is 10 units, not 1.
• Missing NDC on the claim line: Medicare requires the NDC for Part B drugs in a fixed qualifier format. That is qualifier N4, the 11-digit NDC, a unit of measure, then the quantity. Missing or malformed NDC data returns a technical denial that reads like a coverage denial.
• No ABN when coverage is uncertain: The ABN has to be signed before the injection. That applies whenever the diagnosis falls outside the documented indication, or outside the payer’s LCD criteria. It cannot be collected after the denial arrives.

Chasing denials after submission costs far more staff time than preventing them at documentation. Build a pre-claim checklist specific to J2355: Units correct, NDC present, modifier appended, diagnosis linked, and an ABN on file where coverage is uncertain.

Place of service and ASC payment status for J2355

Where the injection is administered changes both the claim form used and the reimbursement logic. HCPCS code J2355 can be billed across several care settings. The place of service (POS) code on the claim must match where the service occurred. Mismatching POS codes is a frequent audit flag for Part B drug claims.

The ASC payment status indicator for J2355 is set in the annual OPPS/ASC final rule. CMS can classify a drug as separately payable in ASCs, bundled into the facility payment, or excluded from ASC payment entirely. Because this designation can change year-to-year, always verify the current indicator before billing J2355 in an ASC setting. The AAPC HCPCS code reference and CMS’s annual payment rule summaries are reliable sources for current ASC status.

NDC to HCPCS J2355 crosswalk

Medicare requires providers to report the National Drug Code (NDC) alongside J2355 on every claim line. The NDC identifies the exact drug product dispensed, including the manufacturer, package configuration, and size. CMS maintains an NDC-to-HCPCS crosswalk file that maps oprelvekin NDC numbers to J2355. That file is updated quarterly, alongside the ASP pricing release.

On the CMS-1500 form, or the 837P electronic claim, the NDC follows a fixed format that the table below sets out. A claim submitted without a properly formatted NDC rejects at the clearinghouse, or draws a technical denial from the MAC. That happens when the correct NDC data is not in the billing system at the moment the claim is created.

Verify the exact NDC for the product you are dispensing against the current CMS NDC-to-HCPCS crosswalk file on CMS.gov. NDCs change when manufacturers update packaging or labeler assignments. The NDC on last year’s claim may not match the vial on the shelf today.

Related and adjacent HCPCS codes

When billing oncology and infusion claims, J2355 rarely appears in isolation. The following codes appear in the same billing contexts and are worth having mapped in your charge description master (CDM) or billing software alongside J2355.

Do not substitute J3490 (Unclassified drugs) for J2355 when billing oprelvekin. J3490 requires an invoice and often triggers a manual pricing determination that delays payment. J2355 remains the specific reportable code, so use it while it is active and appropriate. Code specificity at this level is what separates a clean claim from a reworked one.

How Pabau supports HCPCS J-code billing

Accurate J-code billing depends on the system that captures the data at the point of care. The unit count, the NDC, the route modifier, and the diagnosis link all have to reach the claim. None of them should need manual re-entry from a paper log or a disconnected dispensary record.

Practice management software like Pabau connects clinical documentation directly to the billing queue. When a practitioner records an oprelvekin injection in the patient record, the dose, date, route, and NDC travel with the claim line. No separate billing entry is needed. That connection is where most J-code unit errors disappear. The system derives units from the documented dose, instead of asking a biller to convert milligrams by hand.

J-code accuracy sits alongside eligibility checks, prior authorization tracking, and ERA reconciliation in the revenue cycle. Pabau brings those touchpoints into one platform. An oncology nurse’s administration note then feeds the claim rather than starting a paper trail for billing to chase.

A clean claim for HCPCS code J2355 rests on three elements:

• The right code, with the unit count derived from the documented dose
• A properly formatted NDC on the claim line
• A diagnosis that supports medical necessity

Pabau’s validation checks flag a missing field before the claim leaves the practice. The most common J2355 denial triggers get caught at the source rather than on a remittance three weeks later.

Manage J-code billing without the manual errors

Pabau’s claims management tools help infusion and oncology practices track drug units, append modifiers, and submit clean claims for HCPCS J-codes including J2355. See how the workflow fits your practice.

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Conclusion

Most J2355 denials come down to documentation rather than coverage: A wrong unit count, a missing NDC, an unlinked diagnosis, or a stale ASP rate. Each one is decided before the claim is built, in the clinical note.

Neumega’s discontinuation changes the order of operations rather than the code. J2355 stays active for 2026, so residual stock is still billable. Confirm the product is available first, then check the unit math against the documented dose.

Pabau connects the clinical note to the billing queue, so unit calculations, NDC capture, and modifier selection happen without manual re-entry. If your infusion or oncology practice is losing time to J2355 rework, book a demo to see how the workflow fits your team.

Continue your research

Need a framework for reducing claim denials across your practice? Denial management in healthcare walks through the root-cause categories and the operational fixes that reduce denial rates over time.

Want to understand how drug claims move through the revenue cycle? What revenue cycle management involves explains the end-to-end process from eligibility verification to ERA reconciliation.

Looking for a superbill template that captures J-code details? The superbill guide covers what fields are required for Part B drug claims and how to structure your charge capture forms.

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