FAHCPCS Level II
Left hand, thumb
- Usage notes
- Append to procedure codes performed on the left hand thumb; part of the finger-specific modifier set used for procedures like injections or nail surgery done on individual digits.
- Common mistakes
- Using FA for a toe procedure — FA is hand-specific; toe procedures use the T-series modifiers instead.
Related modifiers
Frequently asked questions
What does modifier FA mean?
Left hand, thumb
When do I use modifier FA?
Append to procedure codes performed on the left hand thumb; part of the finger-specific modifier set used for procedures like injections or nail surgery done on individual digits.
What's a common mistake with modifier FA?
Using FA for a toe procedure — FA is hand-specific; toe procedures use the T-series modifiers instead.
HCPCS modifier data from CMS. CPT® is a registered trademark of the American Medical Association — CPT modifier descriptions are not included on this site. Always verify codes with authoritative sources before making billing decisions.