Modifier 33
Preventive services — when the primary purpose is delivery of an evidence-based service per USPSTF A or B recommendation
✅ When to Use Modifier 33
Screening services (colonoscopy, mammography, etc.) to indicate the primary purpose is preventive. Waives cost-sharing under ACA.
⛔ When NOT to Use Modifier 33
Do NOT use when the reason for the service is diagnostic (symptoms present).
Modifier 33 FAQ
What does modifier 33 mean? +
Preventive services — when the primary purpose is delivery of an evidence-based service per USPSTF A or B recommendation
When should I use modifier 33? +
Screening services (colonoscopy, mammography, etc.) to indicate the primary purpose is preventive. Waives cost-sharing under ACA.
When should I NOT use modifier 33? +
Do NOT use when the reason for the service is diagnostic (symptoms present).
What documentation is required for modifier 33? +
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 July 16, 2026.
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