Convert CPT CODES to ICD-9 Codes for Medical Billing and Coding

Understanding Current Procedural Technology (CPT) Codes

Current Procedural Terminology (CPT) is a code set developed and maintained by the American Medical Association (AMA) that describes medical, surgical, and diagnostic procedures. CPT codes allow for uniform communication, research, and data analysis across local, regional, state, and national bodies. CPT Codes are updated annually on January 1.

Unlike ICD codes, CPT codes are trademarked by the AMA, making it impossible to find a comprehensive list of CPT codes online. But you should still know how to use them to look up procedures and understand their role in the medical billing and coding industry. These five-digit numeric codes identify medical procedures and services in a standardized manner, and are used by physicians, coders, health insurance companies, accreditation agencies, and patients. CPT codes can be used for financial, analytical, and administrative purposes, and are divided into three categories.

CPT Category I Codes

CPT is organized into three distinct categories. The first category, which is by far the largest of the three, contains codes for six subtypes of procedures. Much like ICD-9 and ICD-10, these procedural codes are organized into clusters, which are then subdivided into more specific ranges. For instance, codes for radiology fall in the number range of 70010 to 79999, and codes for a diagnostic ultrasound procedure fall into the range of 76506 to 76999. Within that number range, procedures have a designated code, ensuring healthcare payers record exactly which procedure a patient has undergone. For example, the codes 99213 and 99214, which you may have seen on your medical bill following a checkup, correspond to routine doctor’s visits (of simple and medium complexity, respectively).

As is the case with ICD-9 or ICD-10, the goal of CPT codes is to condense as much information as possible into a uniform language. CPT codes are designed to cover all kinds of procedures and are therefore very specific. For example, the code for a 45-minute session of psychotherapy with a patient and/or family member is 90834, while the code for a 60-minute session with a patient and/or family member is 90837.

CPT Category II Codes

The second section of CPT (Category II, or CPT II) consists of optional supplemental tracking codes. These codes are formatted with a letter as their fifth character, and are coded after the initial CPT code. These Category II codes include information on test results, patient status, and additional medical services performed within the larger Category I procedure. Like Category I codes, they are divided into clusters. CPT II codes for Patient Management, for example, fall into the 0500F-0575F range. While optional, these codes reduce the need for record abstraction and chart review, and lower the administrative burden on healthcare professionals. In addition to increasing efficiency, Category II CPT codes facilitate research and the collection of data related to the quality of patient care. Some codes also relate to state or federal law, as in the case of the codes 3044F-3046F, which document the blood alcohol level of a patient.

These codes are a supplement, not a substitute, for the codes in Category I, and therefore must always be attached to an existing Category I code. An example of a CPT code with a Category II code attached is 80061-3048F, which describes a test of low-density lipoprotein cholesterol (CPT I code 80061), with a result of less than 100 mg of cholesterol per deciliter (CPT II code 3048F).

CPT Category III Codes

The third section of the CPT code is devoted to new and emerging technologies or practices. Note that this code does not indicate that the service performed is ineffectual or purely experimental. A Category III code simply means the technology or service is new and data on it is being tracked. Like Category II codes, Category III CPT codes are numeric-alpha, meaning the last digit is a letter. After a predetermined period of time (typically five years of data tracking), a procedure or technology described by a Category III code may move into Category I, unless it is demonstrated that a Category III code is still needed.

Understand How CPT and ICD-9-CM Codes Interact

CPT codes work in tandem with ICD-9-CM codes to create a comprehensive picture of medical services rendered. ICD-9-CM codes, discussed in detail in Course 10, are numeric (and in certain cases alphanumeric) diagnostic codes that describe the symptoms, area, and type of injury or disease in a patient. When listed together, ICD-9-CM and CPT codes present a picture of both the diagnosis of an injury or disease and the type of service provided to the patient by the healthcare provider.

In some cases, it may be necessary to convert CPT codes to ICD-9-CM codes. ICD-9-CM’s alphanumeric codes describe the services, tests, consultations, and any other way that that a healthcare provider has interacted with a patient. There is often significant overlap between this set of codes and CPT. For instance, the CPT code for two doses of Hepatitis A vaccine, of pediatric or adolescent dosage, for intramuscular use is 90633. The ICD-9-CM code for that same vaccine is V05.3. In general, CPT codes provide more specificity than their ICD-9-CM counterparts. For instance, three doses of the above vaccine is coded in CPT as 90634, while in ICD-9-CM it is still coded as V05.3. Medical coders should familiarize themselves with the equivalencies between these two code systems, and be able to freely translate one into the other.

In addition to converting between these two codes, medical coders must ensure that the code they enter for a medical procedure (the CPT code) makes sense with the diagnosis code (ICD-9-CM). The two codes work in tandem to show which procedure was done for what reason. By confirming that the codes correspond correctly, coders ensure that a claim will not be denied and returned by a health insurance company. For instance, if you submitted a claim for a Human Papilloma Virus vaccine (CPT code 90650), but list the diagnosis as acute appendicitis with generalized peritonitis (ICD-9-CM code 540.0), a health insurance company would catch this error, deny the claim, and return it to you for correction. Lastly, the upcoming switch to ICD-10-CM on October 1, 2014, means that coders should also be able to convert CPT codes into ICD-10-CM codes.