No. J1643 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 J1643?

CMS's ASP crosswalk for October 1, 2026 through December 31, 2026 lists 1 NDC under J1643, for Heparin Sodium (Porcine). The table on this page shows each one with its billing units per package.

What is the Medicare payment limit for J1643?

$2.248 per 1000 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 J1643?

One unit of J1643 is 1000 units, as stated in the code's descriptor. Units to report = dose given ÷ 1000 units.

J1643 J-Code: Heparin sodium — Billing Units & NDCs

In short

J1643 is the HCPCS Level II code for injection, heparin sodium (pfizer), not therapeutically equivalent to j1644, per 1000 units. CMS assigns NDCs for Heparin Sodium (Porcine) to it. One billing unit is 1000 units. The Medicare Part B payment limit is $2.248 per unit (October 1, 2026 through December 31, 2026).

Code

CMS HCPCS file

HCPCS codeJ1643

Billing unit1000 units

Descriptor: Injection, heparin sodium (pfizer), not therapeutically equivalent to j1644, per 1000 units
Short descriptor: Inj heparin, pfizer, 1000u
Code set: HCPCS Level II, maintained by CMS
Effective: Jan 1, 2024

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$2.248

Per1000 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 ÷ 1000 units. For example, 100000 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 = 1,000 units)

Modifier

NDC (11-digit)

NDC unit qualifier

NDC quantity

Enter the dose given to build the claim line.

NDCs billed under J1643

CMS’s ASP NDC–HCPCS crosswalk (effective October 1, 2026 through December 31, 2026) assigns 1 NDC to J1643 for Heparin Sodium (Porcine). Billing units per package are CMS’s figures for this code’s unit.

NDCs assigned to J1643 in the CMS ASP crosswalk
Drug	NDC (11-digit)	Labeler	Package	Billing units per package
Heparin Sodium (Porcine)	00069-0043-01	Pfizer Inc	25 × 2	50

J1643: common questions

Is J1643 a CPT code?: No. J1643 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 J1643?: CMS's ASP crosswalk for October 1, 2026 through December 31, 2026 lists 1 NDC under J1643, for Heparin Sodium (Porcine). The table on this page shows each one with its billing units per package.
What is the Medicare payment limit for J1643?: $2.248 per 1000 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 J1643?: One unit of J1643 is 1000 units, as stated in the code's descriptor. Units to report = dose given ÷ 1000 units. J-code billing units.

J1643 — Injection, heparin sodium (pfizer), not therapeutically equivalent to j1644, per 1000 units