A9531 — Iodine i-131 sodium iodide, diagnostic, per microcurie (up to 100 microcuries)
A9531 is a HCPCS Level II code for iodine i-131 sodium iodide, diagnostic, per microcurie (up to 100 microcuries). 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 A9531 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
- 100 units MAI 3 — Date of Service Edit: Clinical · Code Descriptor / CPT Instruction
- outpatient
- 100 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 A9531
- Long descriptor
- Iodine i-131 sodium iodide, diagnostic, per microcurie (up to 100 microcuries)
- Short descriptor
- I131 max 100uci
- Added
- January 1, 2004
- 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 A9531
HCPCS has no hierarchy — related items simply sit next to each other in the numbering. If A9531 is not quite right, the correct code is very often within a few positions of it.
- A9520Technetium tc-99m tilmanocept, diagnostic, up to 0.5 millicuries
- A9521Technetium tc-99m exametazime, diagnostic, per study dose, up to 25 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
- A9532Iodine i-125 serum albumin, diagnostic, per 5 microcuries
- A9536Technetium tc-99m depreotide, diagnostic, per study dose, up to 35 millicuries
- A9537Technetium tc-99m mebrofenin, diagnostic, per study dose, up to 15 millicuries
- A9538Technetium tc-99m pyrophosphate, diagnostic, per study dose, up to 25 millicuries
- A9539Technetium tc-99m pentetate, diagnostic, per study dose, up to 25 millicuries
- A9540Technetium tc-99m macroaggregated albumin, diagnostic, per study dose, up to 10 millicuries
- A9541Technetium tc-99m sulfur colloid, diagnostic, per study dose, up to 20 millicuries
- A9542Indium in-111 ibritumomab tiuxetan, diagnostic, per study dose, up to 5 millicuries
Questions about A9531
What is HCPCS code A9531?
A9531 is a HCPCS Level II code for iodine i-131 sodium iodide, diagnostic, per microcurie (up to 100 microcuries). It sits in the Transportation, Medical & Surgical Supplies, Administrative section.
Does Medicare cover A9531?
The CMS HCPCS file marks A9531 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 A9531 paid under the physician fee schedule?
A9531 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.