RT and LT Modifiers Fact Sheet
Medicare requires the use of the right (RT) and left (LT) modifiers for certain HCPCS codes. Suppliers must use the RT and LT modifiers when billing 2 of same item or accessory on the same date of service when the items are being used bilaterally.
Suppliers must bill each item on 2 separate claim lines using the RT and LT modifiers and 1 unit of service on each claim line. Do not use the combination RTLT modifier on the same claim line and bill with 2 units of service.
Claim lines for HCPCS codes requiring use of the RT and LT modifiers, billed without the RT and/or LT modifiers or with the RTLT on a single claim line, will be rejected as incorrect coding.
See the following resources for more coding and documentation requirements.
Resources:
- Ankle-Foot/Knee-Ankle-Foot Orthoses (A52457
) - External Breast Prostheses (A52478
) - External Upper Limb Tremor Stimulator Therapy (A59680
) - Eye Prostheses (A52462
) - Facial Prostheses (A52463
) - Knee Orthoses (A52465
) - Lower Limb Prostheses (A52496
) - Lymphedema Compression Treatment Items – Correct Coding and Billing – Revised Joint DME MAC Publication
- Orthopedic Footwear (A52481
) - Refractive Lenses (A52499
) - Surgical Dressings (A54563
) - Therapeutic Shoes for Persons with Diabetes (A52501
) - Standard Documentation Requirements Policy Article (A55426
)
Updated: 08.12.2025

