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HCPCS Q0166 · Level II · Part B drug

HCPCS Q0166: Granisetron hydrochloride, 1 mg, oral, fda approved prescription anti-emetic,

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 Q0166

Billing unit
1 MG
Granisetron hcl 1 mg oral
ASP payment limit
$0.774
October 2026
Practitioner MUE
0
MAI 3
OPPS status
SI N
NCCI exposure
no PTP pairs
Coverage articles
0
none list this code

TL;DR

HCPCS Q0166 is the Level II code for Granisetron hydrochloride, 1 mg, oral, fda approved prescription anti-emetic,, billed per 1 MG. The Medicare Part B ASP payment limit for October 2026 is $0.774 per billing unit. The practitioner MUE allows up to 0 units per date of service (MAI 3). Under OPPS it carries status indicator N. Oral drugs under Part B are payable only in the specific statutory categories (for example oral anticancer or antiemetic drugs with a self-administration exception), so the diagnosis and the regimen must match that category. 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 2 NDCs to it, sold as Granisetron HCl by Breckenridge Pharmaceutical, Inc.. No current Billing and Coding Article lists Q0166, 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 Q0166 at $0.774 per 1 MG for October 2026, derived from manufacturer average sales price plus 6%. Beneficiary coinsurance is 20%.

ASP payment limits for Q0166
QuarterPayment limitPerCoinsurance
October 2026$0.7741 MG20%
July 2026n/a1 MG—
CMS note: Added October 2026

NDC to HCPCS billing-unit conversion

The October 2026 ASP crosswalk maps 2 NDCs from 1 labeler to Q0166. Report the NDC in the claim's drug segment and bill the number of Q0166 units that equals the quantity administered divided by 1 MG; the last column gives units per full package.

NDCs that crosswalk to Q0166
NDCDrug nameLabelerPackage sizeBilling units / package
51991-0735-20Granisetron HClBreckenridge Pharmaceutical, Inc.20 × 120
51991-0735-32Granisetron HClBreckenridge Pharmaceutical, Inc.2 × 12

Medically Unlikely Edits (MUE)

CMS publishes 3 MUE values for Q0166. For practitioners the limit is 0 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 Q0166 by setting
SettingMUE (units/DOS)MAICMS rationale
Practitioner services03 Date of Service Edit: ClinicalOral Medication; Not Payable
Facility outpatient hospital23 Date of Service Edit: ClinicalPrescribing Information
DME supplier23 Date of Service Edit: ClinicalPrescribing Information

NCCI edits and add-on relationships

No active practitioner PTP pair lists Q0166 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.

Q0166 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 Q0166 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, Q0166 carries status indicator N. Status N means payment is packaged into the associated procedure and no separate OPPS payment is made.

Common denials for Q0166 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 Q0166 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 Q0166

What does HCPCS code Q0166 describe?

Q0166 is defined by CMS as "Granisetron hydrochloride, 1 mg, oral, fda approved prescription anti-emetic,". 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 Q0166 in October 2026?

The ASP-based payment limit is $0.774 per 1 MG, with 20% beneficiary coinsurance. Medicare Administrative Contractors apply this limit; commercial payers use their own fee schedules.

How many units of Q0166 can be billed per day?

The practitioner Medically Unlikely Edit is 0 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 "Oral Medication; Not Payable" as the rationale.

Which NDCs map to Q0166?

The October 2026 ASP crosswalk lists 2 NDCs from 1 labeler: Granisetron HCl (Breckenridge Pharmaceutical, Inc.). For example NDC 51991-0735-20 is a 20 package equal to 20 billing units. The crosswalk's billing-units-per-package figure converts each package into Q0166 units.

Does Q0166 have NCCI bundling edits?

No active practitioner PTP pairs list Q0166 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.