How many J2543 billing units are in a package of Zosyn?

CMS lists 48 to 72 billing units per package, depending on the NDC, where one unit is 1.125 gm. Units to report are based on the dose given, not the package.

No. J2543 is a HCPCS Level II code from CMS for the drug itself. Giving it, for example by injection or infusion, is usually reported with a separate CPT administration code.

Zosyn J-Code J2543 — Billing Units & NDCs

In short

Zosyn is billed under HCPCS J2543 — Injection, piperacillin sodium/tazobactam sodium, 1 gram/0.125 grams (1.125 grams). One billing unit is 1.125 gm. CMS's crosswalk lists 3 Zosyn NDCs under this code.

J2543 code details

Reference

J2543: Injection, piperacillin sodium/tazobactam sodium, 1 gram/0.125 grams (1.125 grams)Billing unit: 1.125 gm
Labelers: Baxter Healthcare Corporation

Medicare Part B payment limit

CMS ASP file

Payment limit per unit$1.183

Per1.125 gm

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

Zosyn units and claim line

Enter the dose given to get the J2543 units and the NDC line for the CMS-1500 and the 837P.

HCPCS units

Modifier

NDC (11-digit)

NDC unit qualifier

NDC quantity

Enter the units to build the claim line.

Zosyn NDCs and billing units

From CMS’s ASP NDC–HCPCS crosswalk, effective October 1, 2026 through December 31, 2026. Billing units per package are CMS’s figures for the code’s unit.

Zosyn NDCs in the CMS ASP crosswalk
NDC (11-digit)	HCPCS	Labeler	Package	Billing units per package
00338-9632-24	J2543	Baxter Healthcare Corporation	24 × 1	48
00338-9636-24	J2543	Baxter Healthcare Corporation	24 × 1	72
00338-9638-12	J2543	Baxter Healthcare Corporation	12 × 1	48

Zosyn: common questions

What is the J-code for Zosyn?: Zosyn is billed under HCPCS J2543 — Injection, piperacillin sodium/tazobactam sodium, 1 gram/0.125 grams (1.125 grams). One billing unit is 1.125 gm. CMS's crosswalk lists 3 Zosyn NDCs under this code.
How many J2543 billing units are in a package of Zosyn?: CMS lists 48 to 72 billing units per package, depending on the NDC, where one unit is 1.125 gm. Units to report are based on the dose given, not the package.
Is J2543 a CPT code?: No. J2543 is a HCPCS Level II code from CMS for the drug itself. Giving it, for example by injection or infusion, is usually reported with a separate CPT administration code.

Zosyn J-Code / HCPCS Code