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HCPCS J0594 · Level II · Part B drug

HCPCS J0594: injection, busulfan, 1 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 J0594

Billing unit
1 MG
Busulfan injection
ASP payment limit
$0.839
October 2026; -18.8% vs July 2026
Practitioner MUE
320
MAI 3
OPPS status
SI K
APC 1178
NCCI exposure
no PTP pairs
Coverage articles
0
none list this code

TL;DR

HCPCS J0594 is the Level II code for injection, busulfan, 1 mg, billed per 1 MG. The Medicare Part B ASP payment limit for October 2026 is $0.839 per billing unit, down 18.8% from July 2026. The practitioner MUE allows up to 320 units per date of service (MAI 3). Under OPPS it carries status indicator K in APC 1178. With a 1 mg billing unit, a single administration can be hundreds of units; the unit count on the claim must equal the milligrams given, and rounding rules for partial units follow the contractor's guidance. The ASP crosswalk maps 7 NDCs to it, sold as Busulfan by Pfizer Inc, Accord Healthcare Inc, Sagent Pharmaceuticals. No current Billing and Coding Article lists J0594, 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 J0594 at $0.839 per 1 MG for October 2026, derived from manufacturer average sales price plus 6%, compared with $1.033 in July 2026. Beneficiary coinsurance is 20%.

ASP payment limits for J0594
QuarterPayment limitPerCoinsurance
October 2026$0.8391 MG20%
July 2026$1.0331 MG—
Source: CMS Medicare Part B Drug Payment Limit File. Commercial and Medicaid payers set their own rates.

NDC to HCPCS billing-unit conversion

The October 2026 ASP crosswalk maps 7 NDCs from 7 labelers to J0594. Report the NDC in the claim's drug segment and bill the number of J0594 units that equals the quantity administered divided by 1 MG; the last column gives units per full package.

NDCs that crosswalk to J0594
NDCDrug nameLabelerPackage sizeBilling units / package
00409-1112-01BusulfanPfizer Inc10 × 8480
16729-0351-92BusulfanAccord Healthcare Inc10 × 8480
25021-0241-10BusulfanSagent Pharmaceuticals10 × 8480
59148-0070-91BusulfanOtsuka America Pharmaceuticals Inc.10 × 8480
67457-0893-08BusulfanMylan Institutional LLC10 × 8480
70860-0216-10BusulfanAthenex Pharmaceutical Division, LLC10 × 8480
71288-0116-11BusulfanMeitheal Pharmaceuticals Inc.10 × 8480

Medically Unlikely Edits (MUE)

CMS publishes 3 MUE values for J0594. For practitioners the limit is 320 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 J0594 by setting
SettingMUE (units/DOS)MAICMS rationale
Practitioner services3203 Date of Service Edit: ClinicalPrescribing Information
Facility outpatient hospital3203 Date of Service Edit: ClinicalPrescribing Information
DME supplier03 Date of Service Edit: ClinicalCMS Policy

NCCI edits and add-on relationships

No active practitioner PTP pair lists J0594 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.

J0594 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 J0594 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, J0594 carries status indicator K and is assigned to APC 1178, with a published national unadjusted payment of $1.03. Status K means the drug is paid separately under OPPS at the ASP-based rate rather than packaged into the procedure.

Common denials for J0594 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 J0594 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.

Explore QuickCodeExplore QuickRCMBook a demo

Frequently asked questions — HCPCS J0594

What does HCPCS code J0594 describe?

J0594 is defined by CMS as "injection, busulfan, 1 mg". Each billing unit represents 1 MG, so the units reported on the claim must equal the dose administered divided by that unit.

What is the Medicare reimbursement for J0594 in October 2026?

The ASP-based payment limit is $0.839 per 1 MG, with 20% beneficiary coinsurance. Medicare Administrative Contractors apply this limit; commercial payers use their own fee schedules. The July 2026 limit was $1.033.

How many units of J0594 can be billed per day?

The practitioner Medically Unlikely Edit is 320 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 J0594?

The October 2026 ASP crosswalk lists 7 NDCs from 7 labelers: Busulfan (Pfizer Inc); Busulfan (Accord Healthcare Inc); Busulfan (Sagent Pharmaceuticals); Busulfan (Otsuka America Pharmaceuticals Inc.). For example NDC 00409-1112-01 is a 10 package equal to 480 billing units. The crosswalk's billing-units-per-package figure converts each package into J0594 units.

Does J0594 have NCCI bundling edits?

No active practitioner PTP pairs list J0594 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.