Anesthesia Modifier "AA"

Hi all,

I am a newbie and need some info regarding mod -AA.

1) I notice that this particular modifier is not in the CPT book modifier list but only in the HCPCS book. Does that mean it can only be used with HCPCS codes? If so can you provide an example of a code?

2) The mod is defined as "Anesthesia Services Performed Personally by Anesthesiologist". Since the presumption is that an anesthesiologist will always be the primary person to administer anesthesia, under what conditions would the -AA mod be required?

3) Does the use of this modifier by an anesthesiologist employed by an ASC have any effect on the fee an ASC can receive?

Thanks in advance.

David

Anesthesia Modifier "AA"