C2637: Brachytherapy source, non-stranded, ytterbium-169, per source
C2637 is a HCPCS Level II code for brachytherapy source, non-stranded, ytterbium-169, per source. It belongs to the Outpatient Prospective Payment System 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 2026Q4-Oct. This states Medicare’s position on the code, not on your particular claim.
Medically Unlikely Edits: units per day
The most units of C2637 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
- 0, never payable MAI 3: Date of Service Edit: Clinical · Drug discontinued
- outpatient
- 0, never payable MAI 3: Date of Service Edit: Clinical · Drug discontinued
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 2026Q4.
The CMS record for C2637
- Long descriptor
- Brachytherapy source, non-stranded, ytterbium-169, per source
- Short descriptor
- Brachy,non-str,ytterbium-169
- Added
- October 1, 2005
- BETOS
- I4B
- Pricing indicator
- 53: 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.
Statute.
Codes adjacent to C2637
HCPCS has no hierarchy: related items simply sit next to each other in the numbering. If C2637 is not quite right, the correct code is very often within a few positions of it.
- C2627Catheter, suprapubic/cystoscopic
- C2628Catheter, occlusion
- C2629Introducer/sheath, other than guiding, other than intracardiac electrophysiological, laser
- C2630Catheter, electrophysiology, diagnostic/ablation, other than 3d or vector mapping, cool-tip
- C2631Repair device, urinary, incontinence, without sling graft
- C2634Brachytherapy source, non-stranded, high activity, iodine-125, greater than 1.01 mci (nist), per source
- C2635Brachytherapy source, non-stranded, high activity, palladium-103, greater than 2.2 mci (nist), per source
- C2636Brachytherapy linear source, non-stranded, palladium-103, per 1 mm
- C2638Brachytherapy source, stranded, iodine-125, per source
- C2639Brachytherapy source, non-stranded, iodine-125, per source
- C2640Brachytherapy source, stranded, palladium-103, per source
- C2641Brachytherapy source, non-stranded, palladium-103, per source
- C2642Brachytherapy source, stranded, cesium-131, per source
- C2643Brachytherapy source, non-stranded, cesium-131, per source
- C2644Brachytherapy source, cesium-131 chloride solution, per millicurie
- C2645Brachytherapy planar source, palladium-103, per square millimeter