What is the difference between modifier 33 vs modifier PT

Modifier 33 vs Modifier PT: What’s the difference?

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Modifier 33 and Modifier PT are both used in medical billing, particularly in the United States, but they serve different purposes:

Modifier 33 

This modifier is used when providing preventive services. When added to a claim, Modifier 33 indicates that a procedure or service was a part of preventive care, which under the Affordable Care Act, should not be subject to any copayment, coinsurance, or deductible. 

This helps in ensuring that the billing process reflects that the service should be fully covered by the patient’s insurance, as it is preventive.

Modifier PT 

This modifier is specifically used when a colorectal cancer screening test is converted to a diagnostic test or therapeutic service. For example, if a patient undergoes a screening colonoscopy, which is normally a preventive service, and during the procedure, a polyp is discovered and removed, the procedure is then billed as therapeutic. 

Modifier PT tells the insurer that the procedure started as a screening but shifted to therapeutic due to findings during the procedure, which may impact how the insurance benefits are applied.

How modifiers impact insurance providers

Key Details of Modifier PT

Purpose: The main purpose of Modifier PT is to inform the insurance payer that a procedure began as a preventive screening but shifted to a diagnostic or therapeutic procedure due to findings during the test. 

For example, if a polyp is detected and removed during a screening colonoscopy, the procedure then transitions from purely preventive to therapeutic.

Insurance Impact: The use of Modifier PT can affect how insurance claims are processed and paid. 

Under certain health insurance policies, preventive screenings like colonoscopies are covered at 100%, with no out-of-pocket costs to the patient. However, when these procedures are converted into therapeutic services, some costs may become the patient’s responsibility depending on their insurance plan’s details.

Billing: By applying Modifier PT, healthcare providers can accurately represent the nature of the service on their billing claims, ensuring that they are compliant with insurance regulations and that patients are billed correctly based on the specifics of their insurance coverage.

Key Details of Modifier 33

Purpose: Modifier 33 is to indicate that a service or procedure is provided as a preventive service. This modifier helps ensure that the procedure is accurately documented as preventive, which is significant for insurance billing purposes.

Insurance Impact: The ACA requires most health plans to cover a set of preventive services at no cost to the patient. This means that services billed with Modifier 33 should not be subject to copayments, coinsurance, or deductibles, thereby removing financial barriers to necessary preventive care.

Applicability: It is applicable to a wide range of preventive services such as screenings, immunizations, and counseling on various health conditions. For example, services like cholesterol screenings, mammography, vaccinations, and many others that are considered preventive can be appended with Modifier 33.

Example: If a patient receives a vaccination that is part of the recommended immunization schedule, the healthcare provider would attach Modifier 33 to the billing code for the vaccination. This notifies the insurance company that the service is preventive, and under the ACA, the patient should not be charged any copay, deductible, or coinsurance.

Importance in Billing:

Using Modifier 33 correctly is vital for healthcare providers as it directly influences how patients are billed and how services are reimbursed by insurers. It helps ensure compliance with federal regulations concerning preventive health coverage and facilitates the accurate processing of health insurance claims.

Overall, Modifier 33 is an essential tool in the administration of preventive health services. It helps to promote broader access to preventive care, which is a cornerstone of efforts to improve public health outcomes and reduce healthcare costs over time.

Instructions and Guidelines 

Modifier 33: Preventive Services 


Applicability: Modifier 33 should be attached to services that are identified as preventive under the Affordable Care Act (ACA). This includes a broad range of preventive services recommended by the U.S. Preventive Services Task Force (USPSTF), CDC immunization schedules, and services prescribed in preventive care guidelines for children, adolescents, and women.

Insurance Coverage: Services appended with Modifier 33 are covered without patient cost-sharing (no copayment, deductible, or coinsurance) when provided by an in-network provider. This applies to most private health plans and insurance policies under the ACA.

Documentation: Healthcare providers should ensure that documentation supports the preventive nature of the service. Clear documentation is crucial in case of audits or disputes with insurance companies regarding the application of Modifier 33.

Instructions for Use

Placement: Modifier 33 should be placed next to the CPT code on the billing statement for the preventive service.

Multiple Services: If multiple services are provided during a visit, and only some are preventive, Modifier 33 should only be applied to those services that are preventive.

Modifier PT: Colorectal Cancer Screening Tests Turned Diagnostic 


Applicability: Modifier PT is used specifically for colorectal cancer screening procedures that transition to diagnostic or therapeutic services. This is common in procedures like colonoscopies, where a screening might lead to the removal of a polyp.

Insurance Impact: The use of Modifier PT signals to the insurance company that while the procedure started as a screening (typically covered at no cost under preventive care), it included diagnostic or therapeutic elements. This can affect how the patient’s coverage handles cost-sharing and deductible applicability.

Documentation: Accurate and detailed medical records must support the use of Modifier PT, noting exactly when and why the procedure transitioned from a screening to a therapeutic service.

Instructions for Use

Placement: Attach Modifier PT directly to the CPT code that describes the colorectal screening test when submitting billing claims.

Communication with Payers: Ensure that communications with payers are clear about the use of Modifier PT to preempt any confusion about patient charges and insurance claims processing.


For Modifier 33: A patient’s cholesterol screening (CPT code 80061) is entirely preventive. The healthcare provider attaches Modifier 33 to this code on the claim form to indicate no cost-sharing should be applied.

For Modifier PT: During a routine colonoscopy (CPT code 45378), a polyp is found and removed (CPT code 45385). Modifier PT is attached to 45385, signaling that the procedure shifted from preventive screening to therapeutic intervention.

These guidelines help ensure that the billing for preventive and diagnostic services is handled correctly, minimizing financial surprises for patients and streamlining the reimbursement process for healthcare providers.


Modifiers like 33 and PT are important administrative tools and are integral to the ethical and accurate billing practices in healthcare. They help bridge the gap between healthcare delivery and billing, ensuring that patients receive the benefits of their insurance coverage as intended while providers maintain compliance with billing regulations. Understanding and using these modifiers correctly is essential for the smooth operation of healthcare services and the financial well-being of patients.

Want to get your modifiers right? Contact us today to make your billing processes error-free!

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