A9521 — Technetium tc-99m exametazime, diagnostic, per study dose, up to 25 millicuries
A9521 is a HCPCS Level II code for technetium tc-99m exametazime, diagnostic, per study dose, up to 25 millicuries. It belongs to the Transportation, Medical & Surgical Supplies, Administrative section. Whether Medicare pays it depends on the coverage rule below.
Medicare coverage: Carrier judgment
Coverage is decided by your Medicare contractor, not by national policy. Whether this is paid depends on the LCD for your jurisdiction and on what the documentation supports.
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 statusC
Contractor-priced. Your MAC establishes the RVUs and the payment amount case by case, usually after reviewing documentation. There is no national amount to compute.
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 A9521 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
- 2 units MAI 3 — Date of Service Edit: Clinical · Code Descriptor / CPT Instruction
- outpatient
- 2 units MAI 3 — Date of Service Edit: Clinical · Code Descriptor / CPT Instruction
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 A9521
- Long descriptor
- Technetium tc-99m exametazime, diagnostic, per study dose, up to 25 millicuries
- Short descriptor
- Tc99m exametazime
- Added
- January 1, 2003
- BETOS
- I1E
- Pricing indicator
- 57 — 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.
Other carrier priced.
Codes adjacent to A9521
HCPCS has no hierarchy — related items simply sit next to each other in the numbering. If A9521 is not quite right, the correct code is very often within a few positions of it.
- A9509Iodine i-123 sodium iodide, diagnostic, per millicurie
- A9510Technetium tc-99m disofenin, diagnostic, per study dose, up to 15 millicuries
- A9512Technetium tc-99m pertechnetate, diagnostic, per millicurie
- A9513Lutetium lu 177, dotatate, therapeutic, 1 millicurie
- A9515Choline c-11, diagnostic, per study dose up to 20 millicuries
- A9516Iodine i-123 sodium iodide, diagnostic, per 100 microcuries, up to 999 microcuries
- A9517Iodine i-131 sodium iodide capsule(s), therapeutic, per millicurie
- A9520Technetium tc-99m tilmanocept, diagnostic, up to 0.5 millicuries
- A9524Iodine i-131 iodinated serum albumin, diagnostic, per 5 microcuries
- A9526Nitrogen n-13 ammonia, diagnostic, per study dose, up to 40 millicuries
- A9527Iodine i-125, sodium iodide solution, therapeutic, per millicurie
- A9528Iodine i-131 sodium iodide capsule(s), diagnostic, per millicurie
- A9529Iodine i-131 sodium iodide solution, diagnostic, per millicurie
- A9530Iodine i-131 sodium iodide solution, therapeutic, per millicurie
- A9531Iodine i-131 sodium iodide, diagnostic, per microcurie (up to 100 microcuries)
- A9532Iodine i-125 serum albumin, diagnostic, per 5 microcuries
Questions about A9521
What is HCPCS code A9521?
A9521 is a HCPCS Level II code for technetium tc-99m exametazime, diagnostic, per study dose, up to 25 millicuries. It sits in the Transportation, Medical & Surgical Supplies, Administrative section.
Does Medicare cover A9521?
The CMS HCPCS file marks A9521 as "Carrier judgment". Coverage is decided by your Medicare contractor, not by national policy. Whether this is paid depends on the LCD for your jurisdiction and on what the documentation supports.
How is A9521 paid under the physician fee schedule?
A9521 carries PFS status code C. Contractor-priced. Your MAC establishes the RVUs and the payment amount case by case, usually after reviewing documentation. There is no national amount to compute.