CPT vs. ICD-10 Codes: Mapping the ‘Why’ and ‘What’ of Rehab Therapy Patient Journeys

Physical therapy is a fundamental component of the healthcare system, as evidenced by the more than 300 million rehabilitation sessions that occur annually. Patients seek your clinical expertise to improve their functional health and overall quality of life. However, it’s not just this alone that leads to excellent care and profitability. In addition to your extensive knowledge, your practice’s success also relies on your familiarity with the symbiotic code-based languages known as ICD-10 and CPT codes. 

These healthcare codes play essential roles in patient care, reimbursement, and data analysis, but they signify different things. Each is an important piece in the patient journey puzzle, and when combined, they reveal a complete picture that healthcare professionals, insurers, and more can understand to better treat patients together. Below, we’ll dive into CPT vs ICD-10 codes in rehab therapy, so you understand how they differ, why they’re important, and how to use them in correctly. 

What Are CPT Codes? 

Published in 1966, Current Procedural Terminology codes, also known as CPT® codes, are a standardized coding system used to describe the specific services and procedures provided to patients. In documentation, they primarily explain the “what”, as it relates to the services and treatments carried out during a patient encounter. 

The 1st edition of CPT codes primarily included surgical procedures but has since expanded significantly to encompass other specialties, like rehab therapy. In rehab therapy, these codes include everything from initial patient evaluations to the specific exercises, manual therapies, and modalities applied during a session.

Who Manages CPT Codes?

Created and managed by the American Medical Association (AMA), CPT codes were established to provide physicians and other qualified healthcare professionals with a uniform way of communicating with others about the procedures they perform. Yet, they’ve also been used to fulfill the following: 

• Completing claims processing
• Creating guidelines for medical care review
• Assisting with medical education and research 

The CPT Editorial Panel, a component of the AMA, ensures that these codes remain current and accurately represent the latest medical care provided to patients. The panel consists of 21 members, 12 of whom are appointed by national medical specialty societies, such as the American Academy of Physical Medicine & Rehabilitation. The panel meets three times a year, updates the codes annually, and has the final say in assigning which category a CPT code will be placed. Major changes to the code are made every 10 to 15 years. 

Today, they’re regarded as the most widely accepted coding system to convey medical services and procedures under private and public insurance programs. 

How Are CPT Codes Formatted? 

All CPT codes are five characters long, and the majority of them fall into Category I, which are numeric. Other categories of CPT codes are alphanumeric. As a rehab therapy professional, you’ll primarily need to know about Category I CPT codes. However, you should be aware of Category II and III codes, as those relate to performance improvement and emerging technologies. 

Every CPT code has a corresponding description that clearly explains the procedure or service it represents. For example, 97116 states: “The provider instructs the patient in the proper ways of practicing various exercises, including climbing stairs, focusing on one or more areas, that assist them in walking comfortably and without strain for a period of 15 minutes.” This time-based code is intended for use when physical or occupational therapists perform gait training. 

That’s just one example, but there are over 11,000 CPT codes available for use. 

Frequently Used CPT Codes in Rehab Therapy 

• CPT Code 97110 – Therapeutic exercises
• CPT Code 97140 – Manual therapy techniques
• CPT Code 97530 – Therapeutic activities
• CPT Code 97150 – Group therapy
• CPT Code 97115 – Neuromuscular re-education

What Are ICD-10 Codes? 

The International Classification of Disease system, or ICD, is a classification system developed to accurately track and classify the causes of injuries and deaths in a population. These codes explain “why” a patient is receiving care by highlighting the underlying diagnosis or condition that necessitates treatment. They also aid with billing, conveying clinical communication, care management, quality initiatives, and more. 

When ICD-1 was adopted in 1900, it was based on the Bertillon Classification of Causes of Death, and as a result, focused heavily on mortality data. Since then, 11 revisions have been made, and the currently utilized version, ICD-10, which was published in 1990, now includes several disease categories and much greater detail. 

As a rehab therapist, you’d use ICD-10 codes to communicate the medical necessity for the therapy being provided. For example, suppose a patient is recovering from a heart attack and requires physical or occupational therapy. In that case, the ICD-10 code for an unspecified acute myocardial infarction diagnosis (i.e., I21.9) might be used to document the condition.

Who Manages ICD-10 Codes? 

In 1948, the World Health Organization (WHO) took responsibility for publishing the ICD. Today, the system is developed in collaboration with 10 international centers, including the National Center for Health Statistics. 

The United States has developed its own variations of ICD-10, referred to as ICD-10-CM (ICD-10 Clinical Modification) and ICD-10-PCS (ICD-10 Procedure Coding System). They designed the CM expansion to capture more comprehensive morbidity data and to allow for more frequent updates, whereas the PCS version is for documenting inpatient procedures performed in hospitals. The Centers for Medicare and Medicaid Services (CMS) oversees and publishes system changes annually, on October 1. 

How Are ICD-10 Codes Formatted? 

ICD-10 codes are alphanumeric and can be up to seven characters long. Each code starts with a letter, followed by two numbers. The first three characters identify the category of diagnosis. For example, the characters I63 stands for cerebral infarction, or stroke. 

Following the decimal after the third character, you’ll find characters four through six. They provide more details, such as the cause of the disease, its severity, or the location within the body. 

For context, let’s take the I63 example for stroke. It’s not at all uncommon for rehabilitation professionals to support patients who’ve experienced one. Now, take a close look at the following examples and observe how each additional character gives more specificity. 

• I63.0: Cerebral infarction due to thrombosis of precerebral arteries
• I63.01: Cerebral infarction due to thrombosis of the vertebral artery
• I63.011: Cerebral infarction due to thrombosis of the right vertebral artery

Finally, if you see a 7th character, this is considered an extension. It indicates the type of encounter (e.g., initial, subsequent, sequela) the patient experienced. 

As you can see, ICD-10 codes provide a wealth of information, which is why there are so many of them. In fact, there are currently over 68,000 diagnosis codes and more than 85,000 procedure codes. Don’t forget, however, that specificity of code isn’t a replacement for high-quality, detailed documentation.

ICD-10 vs CPT Codes

After reading about each coding system, did you notice any ways that they’re similar? There are many similarities between the two, which is one of the reasons they can be such a headache to deal with for practitioners and medical coders.

Both CPT and ICD-10 codes: 

• Affect patient care, as they describe what services they’ve had and why, which helps dictate future treatment 
• Systematize communication in healthcare
• Aid with collecting and analyzing healthcare data 
• Are required components when submitting medical claims for reimbursement 
• Are medical coding sets mandated by the Health Insurance Portability and Accountability Act (HIPAA) for electronic transactions of health care information

Key Differences Between CPT Codes and ICD-10 Codes

ICD-10 and CPT codes are both integral to rehab therapy, yet each plays a distinctly different role in the healthcare industry. If rehab practitioners hope to thrive, you need to have a firm grasp of their differences. 

Purpose: Procedure vs. Diagnosis

One of the core differences between ICD-10 and CPT codes lies in what they represent. 

CPT Codes: Focuses on Procedures 

CPT codes are used to explain the specific service provided in response to a patient’s condition. This means that when a rehab therapist or another qualified healthcare professional documents the treatment given to a patient in the electronic health record (EHR), an applicable CPT code is attached. 

For example, if you provide 15 minutes of direct one-on-one therapeutic exercises to improve range of motion for a patient with neck pain, CPT code 97110 might be utilized. 

ICD-10 Codes: Focuses on Diagnosis 

In order to provide medical services, you must establish why it’s needed, and that requires having diagnostic information. ICD-10 codes provide the reason patients need treatment like physical therapy, and if you fail to establish medical necessity, you’ll run into reimbursement issues later. In fact, ICD-10 codes are the primary means by which medical necessity is established in healthcare billing and documentation.

So, if a patient visits your practice for physical therapy and there isn’t a documented reason (ICD-10 code) that justifies the treatment, it’s doubtful that insurance will cover the service. However, if you perform therapeutic exercises on a patient presenting with general neck pain (M54.2 is the ICD-10 code), coverage is more likely since a code is explaining to insurers why you’re providing treatment. 

Documentation: When Are These Codes Applied? 

The time at which each code is used is also a point of differentiation between ICD-10 and CPT codes.

CPT Codes: Applied at Each Treatment Session

Unlike ICD-10 codes, CPT codes are used during every treatment session, as they’re billed per date of service. It’s also possible that every session will include more than one CPT code to detail what was completed during the appointment, whether it’s an initial evaluation, hands-on treatment, or follow-up procedure. The use of multiple codes is common because every service has its own CPT code, ensuring that the therapy provided is accurately recorded in the patient’s record. 

CPT codes are also used to document remote therapeutic monitoring (RTM) services that may occur between rehab therapy visits. 

ICD-10 Codes: During the Initial Evaluation

For the most part, ICD-10 codes are used in the initial evaluation of a patient, as that’s when rehab practitioners provide a clinical rationale for why rehab therapy is needed. This may also be done by a physician, whether a specialist or surgeon, as with a post-surgical patient, or by a primary care physician, who might be diagnosing a lingering injury for a patient. As previously mentioned, any clinician diagnosing an issue that would require rehab therapy must demonstrate that a patient requires or would benefit from that treatment.   

For example, if a patient is diagnosed with lateral epicondylitis (tennis elbow) in the right elbow, the therapist must use ICD-10 code M77.11 to document the condition.

Reimbursement: Medical Necessity vs. Service Payment 

Each code also plays a distinct role in the payer reimbursement process.

CPT Codes: Establishes Reimbursement Rate 

A value is assigned to each CPT code based on three main components measured in Relative Value Units (RVUs). Those RVUs are then converted into a dollar amount using a specific formula that private and public payers use to determine reimbursement rates. 

Since each CPT code is attached to a specific service, it’s important to document as accurately as possible. Many rehab practices underbill because they don’t fully capture all the work they’ve done, leading coders to select a CPT code with a lower dollar reimbursement amount. 

ICD-10 Codes: Confirms Medical Necessity 

Although their role in reimbursement is indirect, it’s incredibly significant. ICD-10 codes help prove that the rehab therapy you’re providing is addressing a legitimate health concern. Without confirming that there’s a valid diagnosis that supports the care provided, insurers may not, and in fact will likely not, approve reimbursement. 

Furthermore, they must match the CPT codes you’ve used. For instance, if the ICD-10 code indicates pain in the left foot (S93.401), but the CPT code lists a treatment forgait training (97116), insurers may consider this a mismatch, resulting in a claim rejection or denial. 

But why is that? Well, a patient having “pain in left foot” doesn’t automatically justify extensive gait training. To avoid hiccups, it would be better to provide documentation and an ICD-10 code that accurately reflects a more comprehensive gait abnormality that the pain is contributing to or is a consequence of. 

Understand the Difference: CPT vs ICD-10 Codes

As we’ve discussed, there’s a lot to know about these two coding systems, and on top of that, they’re regularly changed and updated. Therefore, it’s crucial that rehabilitation practices invest in training and education for their staff on CPT and ICD-10 codes. 

This may involve attending workshops and webinars, as well as collaborating with medical billing and coding experts to stay current. It could also mean implementing a modern physical therapy EHR solution that offers automated coding assistance, which could significantly reduce the guesswork involved in accurate coding processes. 

Remember, these codes are the backbone of the revenue cycle management (RCM) process, which ultimately affects the financial health of your organization. The best thing you can do is stay informed and leverage the tools available to you to decrease administrative burdens and coding hassles.