A guide to CPT codes and how to use them

By Jamie Frew on Jun 19, 2024.

Fact Checked by RJ Gumban.

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An Overview of CPT Coding

CPT Coding, or CPT codes, is a set of medical codes used by healthcare providers to document and classify medical services and procedures. A CPT code is usually a five-digit numeric code, but occasionally it will include an additional letter. A CPT code has no decimal points or other special characters within it.

The American Medical Association (AMA) manages and maintains CPT codes. There is a total of 7,800 CPT codes available. They are updated each year to ensure accuracy and to ensure medical professionals can accurately describe the procedures they’ve performed.

Healthcare providers must submit a claim containing the correct codes based on the CPT code guide to receive service reimbursement.  For example, CPT codes for therapy are used by therapists and healthcare providers to bill for their services.

Insurance companies will then use this information to determine how much they should pay the provider and if additional treatments or tests may be required.

CPT codes have many uses, including billing, reimbursement, and keeping track of medical quality and treatment data. They are also used in clinical research to establish the services provided during the study.

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Importance of CPT codes

CPT codes serve as a common language for healthcare professionals and insurance companies. This ensures everyone is on the same page regarding treatments and services, ensuring accuracy in billing, reimbursement, and quality of care. 

Using CPT codes correctly can help improve patient outcomes by allowing medical professionals to document treatments and procedures accurately. Additionally, accurate CPT coding ensures that patients receive the best healthcare possible. 

Insurance companies also use CPT codes to determine how much they will pay providers for particular procedures. For instance, using CPT codes for family therapy billing is crucial in the medical process. It ensures that the therapist is paid correctly and that family members adequately compensate for their time.

Three categories of CPT codes

There are three categories of CPT codes, and they serve different purposes.

Category I

Category I codes describe medical procedures and services, including surgeries, tests, consultations, and treatments. This category is divided into sections based on the healthcare field they apply to. These sections include:

  • Evaluation and Management
  • Anesthesiology
  • Surgery
  • Radiology
  • Pathology and Laboratory
  • Medicine

Each section consists of a range of five-digit numerical codes assigned to specific services. Apart from CPT codes for Evaluation and Management, the codes are listed in numerical order:

  • Evaluation and Management: 99201 – 99499
  • Anesthesia: 00100 – 01999; 99100 – 99140
  • Surgery: 10021 – 69990
  • Radiology: 70010 – 79999
  • Pathology and Laboratory: 80047 – 89398
  • Medicine: 90281 – 99199; 99500 – 99607 

For example, some of the CPT codes for counseling are 90832 and 90837, while CPT codes for occupational therapy evaluation are 97165, 97166, and 97167.

Category II

Category II codes are used to track performance measurements and other activities. These codes are used with Category I codes to provide additional information about how the service was provided.

For example, a Category II code can indicate whether an experienced professional or a trainee provided a particular treatment or procedure.

These CPT codes can't replace Category I or III codes but rather they provide extra information. They typically contain five characters – the first four numerical characters followed by a fifth alphabetical character, "F":

  • Composite Measures 0001F – 0015F
  • Patient Management 0500F – 0575F
  • Patient History 1000F – 1220F
  • Physical Examination 2000F – 2050F
  • Diagnostic/Screening Processes or Results 3006F – 3573F
  • Therapeutic, Preventive, or Other Interventions 4000F – 4306F
  • Follow-Up or Other Outcomes 5005F – 5100F
  • Patient Safety 6005F – 6045F • Structural 7010F – 7025

Category III

Category III CPT codes report emerging medical services and technologies that don't fit the existing categories. They are used to accurately track new developments in healthcare delivery, such as robotic surgery or teledermatology.

These codes are designed to provide more specificity in coding, and they also help facilities and organizations track the effectiveness of new, emergent medical techniques.

Category III codes may eventually be incorporated into Category I codes if they become widely used or if there is a need for greater specificity. For example, some of the current Category III CPT codes include 94999 for unspecified medical procedures or services and 95930 for biofeedback training.

How are CPT codes used?

Medical coders use CPT codes when filing claims to insurance companies and government agencies. They allow healthcare providers to get paid for their services and help insurance companies accurately track those services.

Do note that there's a difference between CPT codes and HCPS codes. CPT codes are used to describe medical procedures and services. HCPCS codes, on the other hand, are used to identify products, supplies, and services not covered by CPT codes.

 Here's how to use CPT codes:

Initial coding

For initial coding, CPT codes should be selected according to the type of service or procedure provided to a patient. Selecting the correct codes is crucial because it affects the accuracy of filing claims. The reimbursement amount from insurance companies can vary depending on the code chosen.

Verification and submission

Once the codes for service have been chosen, they should be verified against the official CPT coding manual, which stands as a guide for CPT codes. This helps avoid any delays in processing claims. After verifying the codes, you can submit them to insurance companies or government agencies for reimbursement.

 For example, you can use CPT codes for psychological testing and evaluation when submitting Medicare claims for a neuropsychological assessment. CPT codes provide the relevant information needed to track those services and ensure proper payment for the services provided.

Claim processing

Once the codes have been submitted, the insurance company or government agency will review them to ensure they're accurate and used correctly.  The CPT codes are then used to generate an Explanation of Benefits (EOB) that details how much money the patient or provider will receive from the insurance company.


CPT codes help researchers track patient outcomes and the effectiveness of treatments. 

The codes can also be used to compare services across different healthcare providers, allowing for a better understanding of trends in medical practices. This helps researchers determine which treatments are most effective and how they should be used in practice.


CPT codes are essential tools in the healthcare industry since they help track and reimburse medical services. They can also be used for research and to compare treatments across different providers.

By understanding the different types of codes and how to use CPT, healthcare providers can ensure accuracy when filing claims and maximize the reimbursement they receive. And with the right tools and resources, medical coders can easily use CPT codes to ensure accuracy in tracking and filing claims. This will help create a more efficient and cost-effective healthcare system.

Further reading:

CPT® Codes: What Are They, Why Are They Necessary, and How Are They Developed?

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