Compare and Contrast: Modifier 33 and Modifier PT

Remember in high school when your teacher assigned “compare and contrast” essays?  “Compare and contrast Christopher Columbus to John Glenn.”  This article will compare and contrast two recently added modifiers:

  • Modifier 33
  • Modifier PT

Both are new; one was developed by the AMA (modifier 33) and one by CMS (modifier PT).

Let’s start with the CPT modifier.  It is defined as “Modifier 33, Preventive Services: When the primary purpose of the service is the delivery of an evidence-based service in accordance with the US Preventive Services Task Force (USPSTF) A or B rating in effect and other preventive services identified in preventive services mandates (legislative or regulatory), the service may be identified by appending modifier 33, Preventive Service, to the service.”

The USPSTF makes recommendations about preventive and screening services. These recommendations guide medical practices, patients and payers in determining what preventive or screening services are recommended for individual patients.  The Affordable Care Act (ACA), otherwise known as the health care reform bill, requires Medicare to cover  services with an A or B rating at 100%, with no co-pay or deductible for fee-for-service Medicare beneficiaries.  It also mandated that group health insurance policies that renewed after September 2010 provide first dollar coverage for the services with an A or B rating from the USPSTF.  (Group insurers could apply for a waiver and be grandfathered in to that waiver.)  Modifier 33 is used to tell the payer “This is a service that should be processed without a patient due balance, because it was a preventive service with an A or B rating from the USPSTF.”

Not all commercial patients will have this first-dollar coverage, but many with group health insurance plans will have this coverage and more will as time goes on.  Many medical groups that perform these services check the patient’s insurance eligibility and verify benefits before providing the service.  This decreases the likelihood of a denial.

What services have an A or B rating?  You can find them at

What if the group forgets the modifier?  Insurance companies process claims based on the group benefit plan that is built into their system.  The characteristics of the benefit plan are built into the processing: how much is the deductible, what is the co-pay for seeing a specialist, is a preventive service covered?  With or without the modifier, most claims processing systems should pay the claim correctly for these preventive services.  Modifier 33 is a valid CPT modifier and may be used for all payers.  Check with individual payers for their instructions.

Modifier PT is more specialized

Modifier PT is more specialized and will be used by fewer practices.  It is a HCPCS modifier, used to indicate that a colorectal screening service converted to a diagnostic or therapeutic service.  Screening colonoscopies are covered by Medicare without a co-pay or deductible.  These screening colonoscopies are billed with HCPCS codes to Medicare (G0105 and G0120).  A patient who schedules a screening colonoscopy expects that Medicare will pay in full for the procedure.  What if a polyp is discovered? In previous years, this conversion to a therapeutic procedure meant the patient was responsible for a co-pay and deductible.  Talk about adding insult to injury!  Now, however, the surgeon should append modifier PT to the CPT code (not the HCPCS code) that describes the procedure that was performed.  The patient won’t be charged a co-pay or deductible.  For the diagnosis code, use the condition that supports the CPT code, such as polyp or lesion in the first position and the screening diagnosis in the second position.

Should you also append modifier 33, so that the code is submitted as 45380 -PT33?   There is no CPT or CMS guidance about this question.  It would be correct coding to do so.  For Medicare, I would use the PT modifier first.

What about commercial insurance companies?  Should a medical practice also use modifier PT or just modifier 33?  Commercial insurers may also have a differential payment between screening colonoscopies and diagnostic colonoscopies.  For this reason, if a screening colonoscopy converts to a diagnostic service, I would append modifier 33 and PT, in that order. Although CPT doesn’t say this specifically, I would use modifier 33 in the first position for commercial payers, since it is a CPT modifier. It tells the payer that the service started as a preventive service. I would then append modifier PT in the second position.  Not all commercial payers may have this modifier in their system, but if they do, it explains the circumstances.

The purpose of these two modifiers are the same: to tell the payer the service is a preventive one, and should be processed without co-pay or deductible.  There are many services for which modifier 33 is correctly applied. Modifier PT is used only when a colorectal screening converts to a diagnostic or therapeutic service and as such, is more limited in its scope.

About the Author

Betsy Nicoletti is the author of The Field Guide to Physician Coding and founder of She developed The Accurate Coding System to help doctors get paid....

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