No. J1557 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 J1557?

CMS's ASP crosswalk for October 1, 2026 through December 31, 2026 lists 6 NDCs under J1557, for Gammaplex. The table on this page shows each one with its billing units per package.

What is the Medicare payment limit for J1557?

$62.299 per 500 mg, 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 J1557?

One unit of J1557 is 500 mg, as stated in the code's descriptor. Units to report = dose given ÷ 500 mg.

J1557 J-Code: Gammaplex (immune globulin) — Billing Units

In short

J1557 is the HCPCS Level II code for injection, immune globulin, (gammaplex), intravenous, non-lyophilized (e.g., liquid), 500 mg. CMS assigns NDCs for Gammaplex to it. One billing unit is 500 mg. The Medicare Part B payment limit is $62.299 per unit (October 1, 2026 through December 31, 2026).

Code

CMS HCPCS file

HCPCS codeJ1557

Billing unit500 mg

Descriptor: Injection, immune globulin, (gammaplex), intravenous, non-lyophilized (e.g., liquid), 500 mg
Short descriptor: Gammaplex injection
Code set: HCPCS Level II, maintained by CMS
Effective: Jan 1, 2012

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$62.299

Per500 mg

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 ÷ 500 mg. For example, 50000 mg is 100 units. Enter the dose to get the units and the NDC line for the CMS-1500 and the 837P.

Dose given (mg)

HCPCS units (1 unit = 500 mg)

Modifier

NDC (11-digit)

NDC unit qualifier

NDC quantity

Enter the dose given to build the claim line.

NDCs billed under J1557

CMS’s ASP NDC–HCPCS crosswalk (effective October 1, 2026 through December 31, 2026) assigns 6 NDCs to J1557 for Gammaplex. Billing units per package are CMS’s figures for this code’s unit.

NDCs assigned to J1557 in the CMS ASP crosswalk
Drug	NDC (11-digit)	Labeler	Package	Billing units per package
Gammaplex	64208-8234-06	Bio Products Laboratory	100	10
Gammaplex	64208-8234-07	Bio Products Laboratory	200	20
Gammaplex	64208-8234-08	Bio Products Laboratory	100	40
Gammaplex	64208-8235-05	Bio Products Laboratory	50	10
Gammaplex	64208-8235-06	Bio Products Laboratory	100	20
Gammaplex	64208-8235-07	Bio Products Laboratory	200	40

J1557: common questions

Is J1557 a CPT code?: No. J1557 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 J1557?: CMS's ASP crosswalk for October 1, 2026 through December 31, 2026 lists 6 NDCs under J1557, for Gammaplex. The table on this page shows each one with its billing units per package.
What is the Medicare payment limit for J1557?: $62.299 per 500 mg, 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 J1557?: One unit of J1557 is 500 mg, as stated in the code's descriptor. Units to report = dose given ÷ 500 mg. J-code billing units.

J1557 — Injection, immune globulin, (gammaplex), intravenous, non-lyophilized (e.g., liquid), 500 mg