Modifier AT
Acute treatment — chiropractic manipulation for active/corrective treatment
✅ When to Use Modifier AT
Required by Medicare on CPT 98940, 98941, 98942 when chiropractic manipulation treats an acute subluxation or exacerbation of a chronic condition
⛔ When NOT to Use Modifier AT
Do not use for maintenance therapy — Medicare will deny without AT. Use only when active treatment is documented in the note.
Modifier AT FAQ
What does modifier AT mean? +
Acute treatment — chiropractic manipulation for active/corrective treatment
When should I use modifier AT? +
Required by Medicare on CPT 98940, 98941, 98942 when chiropractic manipulation treats an acute subluxation or exacerbation of a chronic condition
When should I NOT use modifier AT? +
Do not use for maintenance therapy — Medicare will deny without AT. Use only when active treatment is documented in the note.
What documentation is required for modifier AT? +
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 April 19, 2026.
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