No. J0598 is a HCPCS Level II code, maintained by CMS, that identifies the drug supplied. CPT codes are five-digit numbers from the AMA that describe services. Giving the drug, for example an injection or infusion, is usually reported with a separate CPT administration code.

What NDCs are billed under J0598?

CMS's ASP crosswalk for October 1, 2026 through December 31, 2026 lists 1 NDC under J0598, for Cinryze. The table on this page shows each one with its billing units per package.

What is the Medicare payment limit for J0598?

$67.065 per 10 units, effective October 1, 2026 through December 31, 2026, from CMS's Part B drug payment limit file. Multiply by the units billed for the allowed amount before deductible and coinsurance. It is not a coverage decision.

What is one billing unit of J0598?

One unit of J0598 is 10 units, as stated in the code's descriptor. Units to report = dose given ÷ 10 units.

J0598 J-Code: C-1 esterase inhibitor — Billing Units

In short

J0598 is the HCPCS Level II code for injection, c-1 esterase inhibitor (human), cinryze, 10 units. CMS assigns NDCs for Cinryze to it. One billing unit is 10 units. The Medicare Part B payment limit is $67.065 per unit (October 1, 2026 through December 31, 2026).

Code

CMS HCPCS file

HCPCS codeJ0598

Billing unit10 units

Descriptor: Injection, c-1 esterase inhibitor (human), cinryze, 10 units
Short descriptor: C-1 esterase, cinryze
Code set: HCPCS Level II, maintained by CMS
Effective: Jan 1, 2011

The billing unit is read from the descriptor. Confirm it against the CMS file before billing.

Medicare Part B payment limit

CMS ASP file

Payment limit per unit$67.065

Per10 units

Coinsurance20%

Effective October 1, 2026 through December 31, 2026. Payment allowance limits subject to the ASP methodology are based on 2Q26 ASP data. A payment limit is not a coverage decision; the Medicare contractor decides coverage. CMS ASP pricing files

Units and claim line

Units = dose given ÷ 10 units. For example, 1000 units is 100 units. Enter the dose to get the units and the NDC line for the CMS-1500 and the 837P.

Dose given (units)

HCPCS units (1 unit = 10 units)

Modifier

NDC (11-digit)

NDC unit qualifier

NDC quantity

Enter the dose given to build the claim line.

NDCs billed under J0598

CMS’s ASP NDC–HCPCS crosswalk (effective October 1, 2026 through December 31, 2026) assigns 1 NDC to J0598 for Cinryze. Billing units per package are CMS’s figures for this code’s unit.

NDCs assigned to J0598 in the CMS ASP crosswalk
Drug	NDC (11-digit)	Labeler	Package	Billing units per package
Cinryze	42227-0083-01	Takeda Pharmaceuticals America, Inc.	1	50

J0598: common questions

Is J0598 a CPT code?: No. J0598 is a HCPCS Level II code, maintained by CMS, that identifies the drug supplied. CPT codes are five-digit numbers from the AMA that describe services. Giving the drug, for example an injection or infusion, is usually reported with a separate CPT administration code. CPT codes for drug administration.
What NDCs are billed under J0598?: CMS's ASP crosswalk for October 1, 2026 through December 31, 2026 lists 1 NDC under J0598, for Cinryze. The table on this page shows each one with its billing units per package.
What is the Medicare payment limit for J0598?: $67.065 per 10 units, effective October 1, 2026 through December 31, 2026, from CMS's Part B drug payment limit file. Multiply by the units billed for the allowed amount before deductible and coinsurance. It is not a coverage decision.
What is one billing unit of J0598?: One unit of J0598 is 10 units, as stated in the code's descriptor. Units to report = dose given ÷ 10 units. J-code billing units.

J0598 — Injection, c-1 esterase inhibitor (human), cinryze, 10 units