HCPCS L3933: Finger Orthosis (FO), without joints, custom

Acquire a list of the documentation and billing requirements needed for proper coding use and billing for HCPCS code L3933 from our short guide.

Use Code

Frequently asked questions

Choose L3933 when a precise anatomical fit is necessary—for instance, due to malunion, swelling, or complex finger contours that off-the-shelf options cannot address.

Yes. For finger orthoses, always use LT or RT modifiers appropriately. If both sides are treated the same day, bill each orthosis on separate lines with the correct side modifier.

A common reason for denial is the "same or similar" rule, where Medicare denies a claim if the patient has received a similar device within the five-year "Reasonable Useful Lifetime" (RUL) of the orthosis. If the patient's needs have changed and the new orthosis is medically necessary, your documentation must clearly explain why the original device is no longer sufficient and why the new one is required.