Difference between CPT and ICD codes

Understanding the intricacies of billing code systems can be challenging. Despite these difficulties, it remains vital to understand the differences between CPT and ICD codes.

Introduction to billing code systems

As we’re sure you know, understanding the intricacies of the healthcare industry can be very challenging. In addition to learning how to use various operational systems, deliver quality care solutions, address patient needs appropriately (have a look at our person first language vs identity first language practice if you want to further understand the role that language plays in the healthcare field), you have to figure out the highly complex medical billing and coding system. Even the most seasoned healthcare practitioners struggle to keep up with the ever-changing codes and how they apply to each field of healthcare. 

Despite these difficulties, it remains extremely important to understand the differences between CPT and ICD codes. Knowing this will help ensure your claims are accurate, reducing the likelihood of receiving claim rejections or denials. Regardless of whether you are working with private payers or payments via insurance providers, understanding medical coding will help your healthcare practice receive reimbursement. In this guide, we’re going to unpack the differences between CPT and ICD codes and equip you with the knowledge you need to become a medical coding expert.

Understanding the terminology of CPT codes and its importance

CPT stands for Current Procedural Terminology codes. Essentially, these codes are used to refer to the different procedures and activities that are completed during a session or interaction with a client. CPT codes are separated into three categories. Category I codes refer to procedures that are generally well-known and frequently used, Category II codes convey information about the quality of care and Category III codes refer to procedures that are newer. Because CPT codes are developed by the American Medical Association (AMA), they are regulated federally. This means that they are applicable to private insurance providers as well as federal government schemes like Medicare and Medicaid. 

CPT codes can change quite frequently, in response to new procedures being introduced into the healthcare industry and for a range of other reasons. While it can be difficult to keep up with these changes, it’s very important that this is an area you encourage your staff to focus on. This will encourage better communication between healthcare providers and ensure that you receive reimbursement at a faster rate. 

What are ICD codes and its importance?

International Classification of Disease (ICD) codes are the other type of code that is commonly used in the healthcare delivery process. These codes are primarily diagnostic; used to explain the specific condition that a client is being treated for. As the title of these codes suggests, ICD is monitored by WHO (World Health Organization) and as such, are internationally regulated. ICD codes are occasionally revisited and revised with minor changes every one to four years and more significant changes around every ten to fifteen years. The ICD-11 is the current code system in place, which went into effect in January 2022.

In addition to communicating diagnoses for clients, ICD codes also assist in observing and assessing health trends around the world. Gathering this type of information is essential to the delivery of quality health care. Because ICD codes are imperative to the insurance process, as well as communicating the health status of clients, it is very important that healthcare practitioners including GPs, licensed therapists, psychologists, psychiatrists, and many other providers have a thorough understanding of them. 

Key differences between CPT and ICD codes

Having a good understanding of CPT and ICD codes will allow you to effectively differentiate between them. While both of these codes play an essential role in establishing communications between healthcare providers and facilities, there are certain key differences that you should be aware of. These include the following: 

Body owning and maintaining the codes

One of the most significant differences between these codes is whose responsibility it is to maintain them. CPT codes are maintained by the American Medical Association whereas ICD codes are organized by the World Health Organization. The most important consequence of this difference is the fact that CPT codes are federal, and ICD codes are international. 

Versions and updates

Another important difference between these codes is how frequently they are updated. Because CPT codes refer to interventions and procedures that occur during interactions with clients, they are changed more regularly. This is largely because new treatments are continuously developed, and CPT codes need to accurately reflect what happened in each client session. On the other hand, ICD codes are only really changed every ten to fifteen years. It is slightly more difficult to regulate codes that are applied internationally (compared to federally), so ICD codes take more time to change. When they are revisited, the new revisions are typically quite significant. 

Number of codes

There is also a difference in the number of individual codes between each of these systems. While there are around 10,000 CPT codes, there are 200,000 codes in ICD-10. 


CPT codes are typically more complex than ICD codes. This is because during a session with a client there is usually more than one intervention or procedure used, and there are multiple different codes and procedures for the same disease/condition. In contrast, there is just one code for each condition and its diagnosis. 

Ways to look up a code for a procedure

Understandably, it is fairly difficult to keep track of every single ICD and CPT code. And while it’s a good idea to remember the codes that will most commonly be used in the private practice or group practice that you work at, there are different ways that you can search codes. ICD codes can be looked up online on the official ICD website. There are pages that index these codes in various ways, helping make the search process easier for all practitioners. On the other hand, CPT code manuals can be accessed, and they can also be found within EHR and practice management systems.


As you know, the medical coding system is extremely complex regardless of what field of healthcare that you work in. Finding the answers to some of the tricky questions in healthcare should hopefully make your job slightly easier, allowing you to spend less time on administrative tasks and instead focus on delivering quality care solutions. We’ve conducted a fair amount of research and developed corresponding guides aimed at supporting healthcare practitioners, so if you are wanting to know more about coding, billing, communications, patient vs client language, different therapy specializations, or anything practice management related then I’m sure we’ll have a resource for you. Hopefully you’ve learned a few things about the differences between CPT and ICD codes and you feel much more confident applying this knowledge to your day-to-day work as a healthcare practitioner.

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