L3999 — Upper limb orthosis, not otherwise specified
L3999 is a HCPCS Level II code for upper limb orthosis, not otherwise specified. It belongs to the Orthotic and Prosthetic Procedures and Devices 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.
Medically Unlikely Edits — units per day
The most units of L3999 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 · CMS Policy
- outpatient
- 2 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 L3999
- Long descriptor
- Upper limb orthosis, not otherwise specified
- Short descriptor
- Upper limb orthosis nos
- Added
- January 1, 1982
- BETOS
- D1F
- Pricing indicator
- 46 — DMEPOS
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.
Carrier priced — not otherwise classified, individual determination, carrier discretion, or gap-filled amounts.
Codes adjacent to L3999
HCPCS has no hierarchy — related items simply sit next to each other in the numbering. If L3999 is not quite right, the correct code is very often within a few positions of it.
- L3976Shoulder elbow wrist hand finger orthosis, abduction positioning (airplane design), thoracic component and support bar, without joints, may include soft interface, straps, custom fabricated, includes fitting and adjustment
- L3977Shoulder elbow wrist hand finger orthosis, shoulder cap design, includes one or more nontorsion joints, elastic bands, turnbuckles, may include soft interface, straps, custom fabricated, includes fitting and adjustment
- L3978Shoulder elbow wrist hand finger orthosis, abduction positioning (airplane design), thoracic component and support bar, includes one or more nontorsion joints, elastic bands, turnbuckles, may include soft interface, straps, custom fabricated, includes fitting and adjustment
- L3980Upper extremity fracture orthosis, humeral, prefabricated, includes fitting and adjustment
- L3981Upper extremity fracture orthosis, humeral, prefabricated, includes shoulder cap design, with or without joints, forearm section, may include soft interface, straps, includes fitting and adjustments
- L3982Upper extremity fracture orthosis, radius/ulnar, prefabricated, includes fitting and adjustment
- L3984Upper extremity fracture orthosis, wrist, prefabricated, includes fitting and adjustment
- L3995Addition to upper extremity orthosis, sock, fracture or equal, each
- L4000Replace girdle for spinal orthosis (ctlso or so)
- L4002Replacement strap, any orthosis, includes all components, any length, any type
- L4010Replace trilateral socket brim
- L4020Replace quadrilateral socket brim, molded to patient model
- L4030Replace quadrilateral socket brim, custom fitted
- L4040Replace molded thigh lacer, for custom fabricated orthosis only
- L4045Replace non-molded thigh lacer, for custom fabricated orthosis only
- L4050Replace molded calf lacer, for custom fabricated orthosis only
Questions about L3999
What is HCPCS code L3999?
L3999 is a HCPCS Level II code for upper limb orthosis, not otherwise specified. It sits in the Orthotic and Prosthetic Procedures and Devices section.
Does Medicare cover L3999?
The CMS HCPCS file marks L3999 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.