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HCPCS Q5146 · Level II · Part B drug

HCPCS Q5146: Injection, trastuzumab-strf (hercessi), biosimilar, 10 mg

Reviewed by QuickIntell RCM Editorial Team · Last reviewed

Data effective
Data currency: ASP payment limits October 2026 (effective October 1, 2026); MUE and NCCI edits 2026 Q4 (effective October 1, 2026); OPPS Addendum B July 2026 (effective July 1, 2026). Next CMS release: January 1, 2027 (ASP, MUE, NCCI and OPPS quarterly updates).

Key facts for Q5146

Billing unit
10 MG
Inj, hercessi, 10 mg
ASP payment limit
$30.255
October 2026; -6.8% vs July 2026
Practitioner MUE
120
MAI 3
OPPS status
SI G
APC 0865
NCCI exposure
no PTP pairs
Coverage articles
0
none list this code

TL;DR

HCPCS Q5146 is the Level II code for Injection, trastuzumab-strf (hercessi), biosimilar, 10 mg, billed per 10 MG. The Medicare Part B ASP payment limit for October 2026 is $30.255 per billing unit, down 6.8% from July 2026. The practitioner MUE allows up to 120 units per date of service (MAI 3). Under OPPS it carries status indicator G in APC 0865. As a biosimilar it has its own code and ASP; the reference product cannot be billed under this code, and the JZ or JW modifier rules for discarded amounts apply per single-dose vial. The 10 mg billing unit means doses are reported in multiples of ten milligrams, with any remainder rounded per contractor policy; mismatched units against the NDC quantity trigger MUE and NDC-unit edits. The ASP crosswalk maps 2 NDCs to it, sold as Hercessi by Accord BioPharma, Inc. No current Billing and Coding Article lists Q5146, so coverage follows the FDA label, compendia and any applicable NCD.

Medicare Part B payment limit (ASP)

CMS sets the Part B payment limit for Q5146 at $30.255 per 10 MG for October 2026, derived from manufacturer average sales price plus 6%, compared with $32.46 in July 2026. Beneficiary coinsurance is 20%.

ASP payment limits for Q5146
QuarterPayment limitPerCoinsurance
October 2026$30.25510 MG20%
July 2026$32.4610 MG—
CMS note: 8% of reference add-on applied

NDC to HCPCS billing-unit conversion

The October 2026 ASP crosswalk maps 2 NDCs from 1 labeler to Q5146. Report the NDC in the claim's drug segment and bill the number of Q5146 units that equals the quantity administered divided by 10 MG; the last column gives units per full package.

NDCs that crosswalk to Q5146
NDCDrug nameLabelerPackage sizeBilling units / package
69448-0015-05HercessiAccord BioPharma, Inc1 × 115
69448-0016-11HercessiAccord BioPharma, Inc1 × 142

Medically Unlikely Edits (MUE)

CMS publishes 3 MUE values for Q5146. For practitioners the limit is 120 units per date of service with adjudication indicator 3, a date-of-service clinical edit: units above the limit deny but can be paid on appeal with documentation that the quantity was medically reasonable.

MUE values for Q5146 by setting
SettingMUE (units/DOS)MAICMS rationale
Practitioner services1203 Date of Service Edit: ClinicalPrescribing Information
Facility outpatient hospital1203 Date of Service Edit: ClinicalPrescribing Information
DME supplier1203 Date of Service Edit: ClinicalPrescribing Information

NCCI edits and add-on relationships

No active practitioner PTP pair lists Q5146 as a column-1 or column-2 code in v323r0. Drug supply codes are rarely bundled; the administration codes billed with them are where PTP edits usually apply.

Q5146 is neither an add-on code nor a designated primary code in the 2026 Q4 NCCI add-on edit file.

Medicare coverage articles

No current Billing and Coding Article lists Q5146 in its HCPCS table. Coverage then follows the drug's FDA label, compendia and any National Coverage Determination; check the Medicare Coverage Database before administering off-label.

Hospital outpatient (OPPS) status

In the July 2026 OPPS Addendum B, Q5146 carries status indicator G and is assigned to APC 0865, with a published national unadjusted payment of $32.46. Status G marks pass-through drug payment, which is time-limited.

Common denials for Q5146 and how to prevent them

CARC 16 · M119

NDC missing, invalid or not matched to the HCPCS code

CARC 151 · N362

units billed exceed the MUE for the date of service

CARC 50 · N115

diagnosis not covered by the applicable coverage article or LCD

How QuickIntell checks Q5146 before the claim leaves

QuickCode validates the NDC-to-unit conversion against the current ASP crosswalk, checks units against every published MUE setting and flags PTP and add-on conflicts on the same claim. QuickRCM routes CARC 16, 151 and 50 denials on drug lines with the matching coverage article attached so the appeal starts with evidence.

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Frequently asked questions — HCPCS Q5146

What does HCPCS code Q5146 describe?

Q5146 is defined by CMS as "Injection, trastuzumab-strf (hercessi), biosimilar, 10 mg". Each billing unit represents 10 MG, so the units reported on the claim must equal the dose administered divided by that unit.

What is the Medicare reimbursement for Q5146 in October 2026?

The ASP-based payment limit is $30.255 per 10 MG, with 20% beneficiary coinsurance. Medicare Administrative Contractors apply this limit; commercial payers use their own fee schedules. The July 2026 limit was $32.46.

How many units of Q5146 can be billed per day?

The practitioner Medically Unlikely Edit is 120 units per date of service with adjudication indicator 3 (3 Date of Service Edit: Clinical). MAI 3 edits can be appealed with documentation that the units were medically reasonable. CMS cites "Prescribing Information" as the rationale.

Which NDCs map to Q5146?

The October 2026 ASP crosswalk lists 2 NDCs from 1 labeler: Hercessi (Accord BioPharma, Inc). For example NDC 69448-0015-05 is a 1 package equal to 15 billing units. The crosswalk's billing-units-per-package figure converts each package into Q5146 units.

Does Q5146 have NCCI bundling edits?

No active practitioner PTP pairs list Q5146 as a column-1 or column-2 code in the v323r0 release. Unit limits (MUE) and medical-necessity coverage rules still apply.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-01. Verify against the primary file before billing or contracting decisions.

Disclaimer

This page is an operational reference compiled from CMS publications: the Medicare Part B drug payment limit and NDC crosswalk files, NCCI MUE and add-on edit tables, aggregate PTP statistics, OPPS Addendum B and the Medicare Coverage Database. Payment limits are Medicare national amounts; commercial and Medicaid payers differ. CPT codes are shown as numbers only; CPT descriptors are copyright AMA. Nothing here is legal, clinical or billing advice.