Modifier AS
Physician assistant, nurse practitioner, or clinical nurse specialist services
✅ When to Use Modifier AS
When a PA, NP, or CNS assists the surgeon. Payment = 13.6% of surgeon fee (lower than MD assistant at 16%).
⛔ When NOT to Use Modifier AS
Do NOT use when a physician assists — use modifier 80.
Modifier AS FAQ
What does modifier AS mean? +
Physician assistant, nurse practitioner, or clinical nurse specialist services
When should I use modifier AS? +
When a PA, NP, or CNS assists the surgeon. Payment = 13.6% of surgeon fee (lower than MD assistant at 16%).
When should I NOT use modifier AS? +
Do NOT use when a physician assists — use modifier 80.
What documentation is required for modifier AS? +
Complete chart documentation supporting the modifier's clinical or billing rationale.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 2, 2026.
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