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HCPCS A9554 · Level II · Part B drug

A9554: iodine i-125 sodium iothalamate, HCPCS Level II drug code

Compiled from CMS files by the QuickIntell RCM Editorial Team · Data effective · Method: reference methodology · Report a data correction

Data currency: OPPS Addendum B: October 2026 (effective October 1, 2026); OPPS NDC-HCPCS crosswalk: October 2026 (effective October 1, 2026); NCCI MUE tables: 2026 Q4 (effective October 1, 2026); NCCI PTP edits: v323r0 (2026 Q4) (effective October 1, 2026); ASC Addendum BB (covered ancillary services): October 2026 (effective October 1, 2026). Next CMS release: January 1, 2027 (quarterly update).

Key facts for A9554

Billing unit
up to 10 microcuries
I125 iothalamate, dx
OPPS payment rate
$649.64
no ASP limit; SI K, October 2026
Practitioner MUE
1
MAI 3
OPPS status
SI K
APC 0863
NCCI exposure
5 col-2 pairs
0% allow a modifier
Coverage articles
0
none list this code

TL;DR

HCPCS A9554 is the Level II code for Iodine i-125 sodium iothalamate, diagnostic, per study dose, up to 10 microcuries, billed per up to 10 microcuries. CMS publishes no ASP payment limit for it; hospital outpatient departments are paid separately under OPPS (status indicator K, $649.64 per billing unit in October 2026). The practitioner MUE allows up to 1 units per date of service (MAI 3). Unlike most diagnostic agents, which OPPS packages into the procedure (status N), A9554 is paid separately in the hospital outpatient department (status K). It is the bundled column-2 code in 5 NCCI pairs, most often with 78122, 78428, 78452. No current Billing and Coding Article lists A9554, so coverage follows the FDA label, compendia and any applicable NCD.

Medicare payment: OPPS rate (no ASP limit)

A9554 does not appear in the October 2026 Part B ASP payment limit file. CMS pays it separately to hospital outpatient departments under OPPS with status indicator K in APC 0863, at a national unadjusted rate of $649.64 per up to 10 microcuries. Status K is a separately paid, non-pass-through drug or biological, including therapeutic radiopharmaceuticals. In a physician office the Medicare contractor prices the drug, often from invoice; commercial and Medicaid payers set their own rates.

NDC to HCPCS billing-unit conversion

The October 2026 OPPS crosswalk lists no NDC for A9554. Report the NDC from the product label and confirm the units conversion from the HCPCS descriptor (Iodine i-125 sodium iothalamate, diagnostic, per study dose, up to 10 microcuries).

Medically Unlikely Edits (MUE)

CMS publishes 2 MUE values for A9554. For practitioners the limit is 1 unit 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 A9554 by setting
SettingMUE (units/DOS)MAICMS rationale
Practitioner services13 Date of Service Edit: ClinicalCode Descriptor / CPT Instruction
Facility outpatient hospital13 Date of Service Edit: ClinicalCode Descriptor / CPT Instruction

MUE for A9554 in every setting opens the lookup with this code filled in, next to any other code on the same claim.

NCCI edits and add-on relationships

In the practitioner PTP file v323r0 (effective October 1, 2026), A9554 is the column-2 code in 5 active pairs, 0% of which allow a modifier (indicator 1), and the column-1 code in 0. 0 historical pairs have been deleted over time. CMS's most frequent rationale: Misuse of Column Two code with Column One code.

When billed with these column-1 codes, A9554 is the bundled component unless the pair allows a modifier and the documentation supports a distinct service.

Column-1 codes most often paired with A9554
Column-1 codePairs
78122 (CPT; descriptor licensed by AMA)1
78428 (CPT; descriptor licensed by AMA)1
78452 (CPT; descriptor licensed by AMA)1
78582 (CPT; descriptor licensed by AMA)1
78707 (CPT; descriptor licensed by AMA)1

The counts above are exposure, not answers for a specific claim. Check A9554 against another code to see whether a given pair bundles, which code is paid and whether a modifier can separate them.

A9554 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 A9554 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 October 2026 OPPS Addendum B, A9554 carries status indicator K and is assigned to APC 0863, with a published national unadjusted payment of $649.64. Status K means the drug is paid separately under OPPS rather than packaged into the procedure.

Ambulatory surgical center (ASC) payment

In the October 2026 ASC Addendum BB (covered ancillary services), A9554 carries payment indicator K2, which CMS defines as "Drugs, biologicals, and radiopharmaceuticals paid separately when provided integral to a surgical procedure on ASC list; payment based on OPPS rate". The national ASC payment is $649.64 per up to 10 microcuries, paid only when the drug is furnished integral to a covered surgical procedure.

Common denials for A9554 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 A9554 before the claim leaves

QuickCode validates the NDC-to-unit conversion against the current OPPS NDC-HCPCS 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 A9554

What does HCPCS code A9554 describe?

A9554 is defined by CMS as "Iodine i-125 sodium iothalamate, diagnostic, per study dose, up to 10 microcuries". Each billing unit represents up to 10 microcuries, so the units reported on the claim must equal the dose administered divided by that unit.

Is A9554 a CPT code?

No. A9554 is a HCPCS Level II code, the letter-plus-four-digit set CMS maintains for drugs such as iodine i-125 sodium iothalamate; CPT codes are five-character codes maintained by the AMA. On a Part B claim A9554 reports the drug itself in up to 10 microcuries units, and the administration is billed on its own line.

What does Medicare pay for A9554 in a hospital outpatient department?

A9554 has no Part B ASP limit; the October 2026 OPPS Addendum B pays it separately under status K, APC 0863, at $649.64 per up to 10 microcuries, and ASC Addendum BB gives it payment indicator K2 at $649.64.

How many units of A9554 can be billed per day?

The practitioner Medically Unlikely Edit is 1 units per date of service with adjudication indicator 3 (Date of Service Edit: Clinical). MAI 3 edits can be appealed with documentation that the units were medically reasonable. CMS cites "Code Descriptor / CPT Instruction" as the rationale.

Does A9554 have NCCI bundling edits?

In the v323r0 practitioner PTP file, A9554 appears as the column-2 (bundled) code in 5 active pairs and as the column-1 code in 0. 0% of the column-2 pairs allow a modifier (indicator 1). The most frequent column-1 partners are 78122, 78428, 78452, 78582, 78707, and CMS's leading rationale is "Misuse of Column Two code with Column One code".

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.

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, ASC Addendum BB and the Medicare Coverage Database. Payment limits and rates 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.

Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.