CPT Codes - What are They, and How Do You Use Them?

CPT codes describe the physical procedures (including injections, lab tests, exams, etc.) that healthcare providers perform when patients come in for an office visit.

Understanding these codes is an essential part of doing your job as a medical coder. Without CPT codes, you cannot bill anything to an insurance company.

There are two basic parts to any medical claim. They are the most important part of describing of what happened at the patient visit. They are the ICD-9 codes (diagnosis) and CPT, or Common Procedural Terminology, codes.

Put together, these two codes explain why the patient came in to the office and how they were treated by the doctor.

The diagnosis, or ICD-9 code, describes the reason why the patient came into the office.

For example, the patient could be suffering from a sore throat, and so he or she would come into the office for pharyngitis (sore throat). The ICD-9 code, then, would be 462.

The next part of the claim would include how the patients were treated in the office. These are the procedures, or CPT medical billing codes.

In other words, the procedures describe what the doctors or nurses did at the office visit to treat the sore throat or to test for any diseases or infections.

In this example, the procedure codes would include an evaluation and management service (99211-99215) and a strep screen to make sure the patient does not have strep throat (87880).

Each one of the procedure codes would be included with the same diagnosis (sore throat).


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How do doctors get paid?

You have to include the CPT code for each procedure

Besides being an essential part of coding any type of doctor visit, CPT procedure codes are the codes that you charge for. When you enter a claim, you will list the procedure code, along with the appropriate diagnosis, in addition to the charges for each specific procedure.

This means that these are the codes that are paid by insurance companies.

An insurance company won't pay just because you tell them that the patient had a sore throat. You have to include CPT codes for each procedure performed, so that the doctor can get paid for each component of the office visit.


Categories in CPT medical coding

There are many categories of CPT medical billing codes. Each category is specific to the type of service.

Most of the major categories correspond to the main systems of the body according to the principles of the anatomy of the human body. They are the following:

  • Anesthesia (00100-01999)
  • Surgery (10021-19499)
  • Musculoskeletal (20005-29999)
  • Respiratory System (30000-32999)
  • Cardiovascular System (33010-37799)
  • Digestive System (40490-49999)
  • Urinary System (50010-53899)
  • Male Genital System (54000-55899)
  • Female Genital System (56405-58999)
  • Nervous System (61000-64999)
  • Eye and Ocular Adnexa (65091-68899)
  • Radiology/Diagnostic Radiology (70010-79999)
  • Pathology and Laboratory (80047-89398)
  • Medicine, Special Services, Procedures and Reports (90281-99607)
  • Evaluation and Management (99201-99499)


Procedure codes and modifiers

Sometimes it's necessary to include a modifier with a procedure code. What this does is change the meaning of the procedure code.

This helps the insurance company understand the service that was provided at the office visit by including additional information.

Modifiers are also sometimes necessary to make sure your claims are paid in full.

Click for more information on medical coding modifiers and how they affect claim payment.


Do you have to know all the procedure codes?

The CPT code manual - you should be very familiar with this!

The CPT manual is a two-pound monster, complete with hundreds of pages and thousands of codes. But don't worry, you normally only need to work a small amount of these codes on a regular basis.

Furthermore, once you become accustomed to reading the code descriptions and finding the codes that you need, using this manual will become a normal part of your daily routine.

Another important thing to note is that most of your procedure codes will be included in your doctor's encounter form, which is a list of all commonly used procedure and diagnosis codes. This form is what you will use to enter the codes for a medical claim.

For more on encounter forms, see our article on encounter forms.


Evaluation and Management codes

You may have noticed on the previous list that there's a small set of codes within another set. These are evaluation and management codes. These describe normal patient office visits and services, and are included in almost every outpatient doctor visit.

Click for more information on evaluation and management services.


How to use the CPT code book?

Now the question remains, how do you actually use the CPT manual to find the right codes? This is probably the most difficult part of being a medical coder. Sometimes it is hard to find exactly the right code, as they are very complex and the CPT manual contains thousands of procedural descriptions.

There is no way we could go into any type of detail in this short amount of space, as this is usually a major part of learning how to be a medical coder. In your medical coding education, you will spend months learning exactly how to find the right code in the CPT manual.

That being said, we can at least learn the basic steps.

  1. First, determine what the procedure was. As in the above example, you can read into it and determine that the procedure was a circumcision.
  2. Next, go to the Index at the back of the CPT manual, and look up circumcision of a neonate (baby). It will direct you to codes 54150 and 54160.
  3. Go to these codes in the Surgery section in the Male Genital System and find both codes.
  4. Read these code descriptions completely and carefully. Notice that 54150 is a circumcision using a clamp or other device, and 54160 is a circumcision using surgical excision other than clamp, device or dorsal slit.
  5. Check your code description to verify what type of surgical excision was used. In this case it was by using a clamp, so our correct code is 54150.

In your actual medical coding education, you will spend many hours studying the CPT coding manual and practicing looking up the correct codes.


Category II and III codes

The 2 additional categories of CPT codes are Category II and Category III. Image copyright National Institutes of Health

There are 2 additional categories of CPT codes: Category II and Category III.

Category II codes are a specific set of codes used to track performance.

They're included in the CPT manual to help decrease the need for record requests and chart reviews.

These codes make it easier for healthcare professionals, office personnel, healthcare practice administrators, hospitals, and other organizations in the medical industry to track performance.

Because Category II codes are optional, they're not a mandatory component of healthcare claims. They're simply additional information which can be used to measure the progress and performance of certain medical personnel.

Furthermore, because they're not necessary components of the coding process, they're not reimbursed by insurance companies. This means Category II codes are not paid components of healthcare claims.

Category III codes are made up of emerging technology, services, and procedures. In other words, they're not federally regulated, and they're new to the healthcare industry. Even though they're emerging codes, you have to use them if they replace an older technology.

Using Category III codes is an important part of keeping the medical community up to date, and supporting advancements in the medical community and healthcare technology.

Knowing and understanding the many types and uses of CPT medical billing codes is a fundamental part of being a successful medical coder.

Keeping up to date with advancements and changes in the medical coding industry, including changes in CPT codes, will help you be the best medical coder you can be.


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