C9121 Injection, argatroban, per 5 mg

HCPCS Code C9121: Injection, Argatroban, Per 5 mg

HCPCS code C9121 identifies an injection of argatroban billed per 5 mg. Public sources establish this code within Medicare claims processing documents and payer code lists, distinguishing it from other argatroban codes based on dosage and patient context. The sources also place this code within specific billing and authorization frameworks. 1 2 3 4 5

Plain-language overview

HCPCS code C9121 represents a healthcare service or supply for an injection of argatroban, calculated for billing purposes at a rate of every 5 milligrams administered. 5

What this code represents

Code C9121 is officially labeled as an injection of argatroban per 5 mg, distinguishing the specific billed dosage unit from alternative argatroban billing codes. 2

Coding details

Source documents distinguish C9121 from J0883, which covers argatroban per 1 mg for non-end-stage renal disease use, and J0884, which covers argatroban per 1 mg for ESRD on dialysis. 2

Coverage and utilization context

One payer's authorization list specifies that HCPCS code C9121 for the argatroban injection does not require prior authorization, while other listed medications on the same document do. 3

A Medicare claims processing transmittal places C9121 under the category of drugs subject to end-stage renal disease consolidated billing for access management. 1

What the sources add

A Medicare transmittal lists C9121 alongside J0883 and J0884 to show code transitions, while a separate payer alert lists C9121 to communicate authorization requirements, illustrating different operational uses. 2 3

A Department of Health Care Services Healthcare Common listing includes C9121 with the description of an injection of argatroban per 5 mg, providing an additional payer-level code directory entry. 4

Documentation considerations

The official descriptor for C9121 defines the billed unit as an injection of argatroban per 5 mg, establishing the specific dosage measurement associated with this healthcare product code. 2 5

Service and patient context

A Medicare claims processing transmittal includes C9121 in a section titled drugs subject to end-stage renal disease consolidated billing under the access management category. 1

Sources

1. Pub 100-04 Medicare Claims Processing — cms.gov; accessed 2026-07-27.
2. Pub 100-04 Medicare Claims Processing — cms.gov; accessed 2026-07-27.
3. Provider Alert - Update to HCPCS Codes Requiring Authorization — amerihealthcaritasla.com; accessed 2026-07-27.
4. Department of Health Care Services Healthcare Common ... — blueshieldca.com; accessed 2026-07-27.
5. In the world of reimbursement, nothing is narrative — pharmacypracticenews.com; accessed 2026-07-27.