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Modifier Coding Alert

Reader Question:

Grasp When You Use Modifier 33

Question: I’ve been told by other coders that I can use modifier 33 on preventive services. Is that correct?

Missouri Subscriber

Answer: Yes, you should use modifier 33 (Preventive services) in some cases, depending on your payer. 

Modifier 33 notifies your payer that the preventive service was performed and that the patient’s deductible and coinsurance do not apply under the new Patient Protection and Affordable Care Act (PPACA) rules.

The PPACA requires all health care insurance plans to cover preventive services and immunizations without any cost sharing. In other words, the payer must provide first-dollar-coverage for certain specified preventive services. 

Downside: According to a Q&A on WPS Medicare’s Web site, Medicare does not recognize modifier 33 (

Reason: Medicare can only pay for preventive services that are specifically legislated and all of these services have their own HCPCS “G” codes to describe them. You can only place modifier 33 on a CPT® code, so modifier 33 isn’t applicable on a Medicare claim anyway.

Some insurers, such as Excellus BlueCross BlueShield, have information regarding modifier 33 on their Web sites. For example, Excellus shares several guidelines for reporting modifier 33, including:

  • CPT® modifier 33 is applicable to preventive services that do not have a unique code for such services (e.g., E&M codes such as 99401 would not require modifier 33 as this code already indicates a preventive medicine service. However, code 99213 would require modifier 33 when the provider indicates that the service was preventive).
  • If multiple preventive medicine services are provided on the same day, then the modifier is appended to the codes for each preventive service rendered on that day.
  • Modifier 33 should be used when only preventive services were rendered on that date, not when combined with other non-preventive services.
  • CPT® codes identified as inherently preventive, (e.g., screening mammography) should not be appended with modifier 33.