Final answer:
The modifier FA is utilized to report procedures performed on the left hand thumb, providing specific detail for medical billing purposes.
Step-by-step explanation:
The modifier FA is indeed utilized to report procedures performed on the left hand thumb. This is a coding convention used to provide further detail on where a procedure was performed for billing and record-keeping purposes. When using the FA modifier, it specifically indicates that the service provided was related to the left thumb, as opposed to other digits of the left hand or the thumb on the opposite hand. The information provided by the FA modifier is critical for clarity in medical billing and to avoid confusion with other digits or limbs.