P9021 — Red blood cells, each unit
P9021 is a HCPCS Level II code for red blood cells, each unit. It belongs to the Pathology and Laboratory Services section. Whether Medicare pays it depends on the coverage rule below.
Medicare coverage: Special coverage instructions apply
There are published conditions attached to this code. Check the applicable coverage policy before billing it: the code being valid is not the same as the service being covered.
From the coverage field of the CMS Alpha-Numeric HCPCS File, release 2026Q3-Jul. This states Medicare’s position on the code, not on your particular claim.
Physician fee schedule statusE
Excluded from the physician fee schedule by regulation. Payment, where it exists, comes from another fee schedule (drugs via ASP, supplies via DMEPOS, and so on).
Global period: XXX
Want the dollar amount for your locality? The fee calculator applies your GPCI and the current conversion factor.
Medically Unlikely Edits — units per day
The most units of P9021 Medicare will pay on one date of service. Bill more on a single line and it is denied. The limit is not the same in every setting, so the row that matters is the one matching the claim you are building.
- practitioner
- 3 units MAI 3 — Date of Service Edit: Clinical · Clinical: Data
- outpatient
- 8 units MAI 3 — Date of Service Edit: Clinical · Clinical: Data
The adjudication indicator decides whether exceeding the limit is worth appealing at all: MAI 1 is a line edit you can support with documentation, MAI 3 is a date-of-service edit that is also appealable, and MAI 2 is absolute — no documentation overrides it. CMS MUE 2026Q3.
The CMS record for P9021
- Long descriptor
- Red blood cells, each unit
- Short descriptor
- Red blood cells unit
- Added
- January 1, 1987
- BETOS
- T1H
- Pricing indicator
- 52 — Other
The official wording. This is what the code means.
CMS's 28-character form, which is what shows up on a remittance advice.
When CMS introduced the code.
Berenson-Eggers Type of Service — CMS's own analytic grouping.
Reasonable charge.
Codes adjacent to P9021
HCPCS has no hierarchy — related items simply sit next to each other in the numbering. If P9021 is not quite right, the correct code is very often within a few positions of it.
- P7001Culture, bacterial, urine; quantitative, sensitivity study
- P9010Blood (whole), for transfusion, per unit
- P9011Blood, split unit
- P9012Cryoprecipitate, each unit
- P9016Red blood cells, leukocytes reduced, each unit
- P9017Fresh frozen plasma (single donor), frozen within 8 hours of collection, each unit
- P9019Platelets, each unit
- P9020Platelet rich plasma, each unit
- P9022Red blood cells, washed, each unit
- P9023Plasma, pooled multiple donor, solvent/detergent treated, frozen, each unit
- P9025Plasma, cryoprecipitate reduced, pathogen reduced, each unit
- P9026Cryoprecipitated fibrinogen complex, pathogen reduced, each unit
- P9027Red blood cells, leukocytes reduced, oxygen/ carbon dioxide reduced, each unit
- P9031Platelets, leukocytes reduced, each unit
- P9032Platelets, irradiated, each unit
- P9033Platelets, leukocytes reduced, irradiated, each unit
Questions about P9021
What is HCPCS code P9021?
P9021 is a HCPCS Level II code for red blood cells, each unit. It sits in the Pathology and Laboratory Services section.
Does Medicare cover P9021?
The CMS HCPCS file marks P9021 as "Special coverage instructions apply". There are published conditions attached to this code. Check the applicable coverage policy before billing it: the code being valid is not the same as the service being covered.
How is P9021 paid under the physician fee schedule?
P9021 carries PFS status code E. Excluded from the physician fee schedule by regulation. Payment, where it exists, comes from another fee schedule (drugs via ASP, supplies via DMEPOS, and so on).