Glossary · Updated Jul 28, 2026
Assistant Surgery Indicator
The assistant surgery indicator tells you whether an assistant at surgery — billed with modifier 80, 82, or AS for a non-physician assistant — can be separately paid for a given procedure, and under what conditions.
The three outcomes
Indicator 2 means an assistant surgeon is payable, typically at a set percentage of the procedure's fee schedule amount. Indicator 0 means payment is restricted unless supporting documentation establishes medical necessity for an assistant. Indicator 1 is a statutory bar: an assistant at surgery may never be separately paid for that procedure, no matter the documentation. Indicator 9 means the concept does not apply — most non-surgical codes fall here.
Assistant surgery indicator values
All four values, in one table:
| Value | Meaning |
|---|---|
| 0 | Restricted — payable only with documentation of medical necessity |
| 1 | Never separately payable (statutory restriction) |
| 2 | Payable |
| 9 | Concept does not apply |
Two modifiers, two percentages
When indicator 2 applies, a physician assistant surgeon (modifier 80 or 82) and a non-physician assistant at surgery (modifier AS, e.g. a PA or NP) are paid at different percentages of the base amount — see the modifier amounts on a code page such as CPT 99213 for the exact figures.
Frequently asked
Can any surgery bill an assistant surgeon?
No. Only procedures with indicator 2 (or, with documentation, indicator 0) support a separately payable assistant surgeon. Indicator 1 procedures never do.
Does modifier AS pay the same as modifier 80 or 82?
No — the non-physician assistant-at-surgery percentage (modifier AS) differs from the physician assistant-surgeon percentage (modifiers 80/82), even for the same procedure.
Sources
- CMS Medicare Physician Fee Schedule Relative Value Files
- CMS Physician Fee Schedule overview (cms.gov)
Written from primary CMS sources — see how we source, compute, and verify everything on this site.
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