General Equivalence Mappings

In healthcare, diagnosis and procedure codes and their attached descriptions are the currency for many critical data transactions. Healthcare organizations rely heavily on coded data to govern reimbursement, monitor the health of the population, track trends in disease and treatment, and optimize the delivery of healthcare in the US.

The possible implementation of the ICD-10 code set is a historic opportunity to upgrade the quality of healthcare data, but like everything worth having, it comes at a cost. One cost is mapping between the old and new code sets.

A recurring theme in the ongoing ICD-10 implementation debate has been the need for a crosswalk between the old and new code sets to help the industry make the transition. The lack of an “official” mapping between ICD-9-CM and ICD-10-CM/-PCS has long been seen as a major challenge to ICD-10 implementation. The General Equivalence Mappings (GEMs) are an attempt to meet that challenge.

What Are GEMs?

The GEMs are the product of a coordinated effort spanning several years and involving the National Center for Health Statistics (NCHS), the Centers for Medicare and Medicaid Services (CMS), AHIMA, the American Hospital Association, and 3M Health Information Systems. The GEM files are a public domain reference mapping designed to give all sectors of the healthcare industry that use coded data a tool to convert and test systems, link data in long-term clinical studies, develop application-specific mappings, and analyze data collected during the transition period and beyond.

It would be impossible to produce a “one size fits all” set of mappings because a mapping is heavily dependent on its purpose. A map for reimbursement uses different rules and contains different entries than a map for research.

The GEMs are more than simple crosswalks. They cannot be used in a legacy system in unaltered form to get from a code in one set to a code in the other. A clear one-to-one correspondence between an I-9 or I-10 code is the exception rather than the rule.

It is useful to think of GEMs as two-way translation dictionaries for diagnosis and procedure codes from which crosswalks can be made for specific purposes. They elucidate the differences between the code sets and assist users in making informed decisions about how to link the codes in a way that meets their needs.

While ICD-9-CM diagnosis codes and ICD-9-CM procedure codes are maintained by two different government entities, the GEMs were developed separately but collaboratively to maintain consistency insofar as possible. The resulting files can be merged seamlessly as needed—subsets extracted, analyzed, and applied—without taking extra steps to make them compatible.

ICD-9 Codes

ICD-9-CM (International Classification of Diseases, 9th edition, Clinical Modifications) is a set of codes used by physicians, hospitals, and allied health workers to indicate diagnosis for all patient encounters. The ICD-9-CM is the HIPAA transaction code set for diagnosis coding.

ICD means International Statistical Classifications of Diseases. ICD codes are alphanumeric designations given to every diagnosis, description of symptoms and cause of death attributed to human beings.

These classifications are developed, monitored and copyrighted by the World Health Organization (WHO). In the United States, the NCHS (National Center for Health Statistics), part of CMS (Centers for Medicare and Medicaid Services) oversees all changes and modifications to the ICD codes, in cooperation with WHO.

Here is how WHO describes the ICD system: ICDs apply to "all general epidemiological, many health management purposes and clinical use. These include the analysis of the general health situation of population groups and monitoring of the incidence and prevalence of diseases and other health problems in relation to other variables such as the characteristics and circumstances of the individuals affected, reimbursement, resource allocation, quality and guidelines."

The current International Classification of Diseases can trace its roots back to the Bertillon Classification first published in 1893. Starting in 1900, experts met about every 10 years under the auspices of the French government to revise the classifications. The fifth revision was published just before World War II. The World Health Organization took over responsibility for ICD in 1946 with publication of ICD-6. The intended purpose of the ICD-9 diagnosis codes (Volume 1 and 2) is for statistical tracking of diseases. Nothing more. Codes are added only when it can be demonstrated that it will help in the identification and monitoring of the disease.

The current edition in the United States for morbidity classification, ICD-9-CM, has been in use since 1979. The original intent for the diagnosis codes was for epidemiological and not billing functions, although in the US, the codes are used by payers for billing and reimbursement purposes.

ICD-9 diagnosis codes consist of 3-5 numeric characters representing illnesses and conditions, and alpha-numeric E codes, describing external causes of injuries, poisonings, and adverse effects; and V codes describe factors influencing health status and contact with health services.

ICD-9-CM consists of three volumes. Physicians use Volumes 1 and 2 only to assign diagnosis codes. Physicians use Current Procedural Terminology (CPT), published by the American Medical Association, to report medical and surgical procedures and physician service codes, rather than Volume 3 of the ICD-9-CM codes. The 3rd Volume of ICD-9-CM is used by Hospitals for reporting inpatient procedures and resource utilization.

There Are Several ICD Code Sets

There are actually several lists of these codes, all of which relate to each other. While the code numbers may be the same, sometimes they will have extra numbers or letters attached to them for different uses. In these examples, the use of # will relate to a number. See a description for these numbers, below.

ICD-##-CM codes are used for diagnosis purposes. CM means "clinical modification." It is used by hospitals and other facilities to describe any health challenges a patient has, from his diagnosis to symptoms to outcomes from treatment, to causes of death. As we move more and more into electronic medical records, these codes will be used even further by physicians and other medical professionals.

ICD codes are used by government health authorities to track certain diseases. For example, if someone contracts the flu, an ICD-9-CM 486 will be recorded. Certain diseases, often those that are highly contagious, or those that have public health interest like lung cancer or HIV, are tracked by authorities to help ascertain how they spread, where they are prevalent, and perhaps to help budget programs or research to work on prevention.

ICD codes are also used to describe a cause of death. They are added to death certificates to explain why someone has died. Many of these, too, are tracked by health authorities.

ICD codes are used internationally (remember, they emanate from WHO) and each country may tailor the codes to fit their own needs. Therefore, some code sets will have extra letters addended to them to describe which country they come from. For example, ICD-##-CA codes are used in Canada and ICD-##-AM codes are used in Australia.

What Do the Numbers Mean? ICD-09, ICD-10 and Others

ICD codes were first developed in 1893 in France by a physician, Jacques Bertillion. They were called the Bertillon Classification of Causes of Death. In 1898, they were adopted in the United States, and were considered, in effect, ICD-1 because that was the first version of code numbers.

Since then, as medical science has progressed and new diagnoses have been developed, named and described, the code lists have been updated. The number designation changes when the updates are so extensive that a wholesale change needs to be made. There may be annual updates, too, but those are considered to be relatively minor, and the basic code set doesn't change. For example, the upgrade in 1949, ICD-6, was the first time mental disorders were added to the code set. The upgrade in 1977 to ICD-9 was the first time procedure codes were added, and the CM designation was included.

Most of the codes we see in the United States today are version 9, called ICD-9-CM codes. With few exceptions, the paperwork we receive when we leave a doctors office will contain both CPT codes (Current Procedural Terminology) to describe the service that was rendered for billing purposes, and ICD-9-CM codes to describe why that service was provided. Further, most death certificates filed since 1977 will have an ICD-9 code on them.

The most current list of codes in use is ICD-10. This list was first used in the United States in 2007. Minor revisions added to ICD-10 codes were made available in early 2009 by the NCHS. Globally, most other countries in the world have implemented the ICD-10 codes. There are some major differences between the two code sets, the transition is very expensive, and most American providers have not yet upgraded to the ICD-10 system.

ICD-11, the next major update, is projected to be ready in 2010, with expected implementation by 2015.

Medical Coding

What is Medical Coding?

Medical classification, or medical coding, is the process of transforming descriptions of medical diagnoses and procedures into universal medical code numbers. The diagnoses and procedures are usually taken from a variety of sources within the health care record, such as the transcription of the physician's notes, laboratory results, radiologic results, and other sources.

Diagnosis codes are used to track diseases and other health conditions, whether they are chronic diseases such as diabetes mellitus and heart disease, to contagious diseases such as norovirus, the flu, and athlete's foot. These diagnosis and procedure codes are used by government health programs, private health insurance companies, workers' compensation carriers and others.

Medical classification systems are used for a variety of applications in medicine, public health and medical informatics, including:

• statistical analysis of diseases and therapeutic actions
• reimbursement; e.g., based on diagnosis-related groups
• knowledge-based and decision support systems
• direct surveillance of epidemic or pandemic outbreaks

What does a Medical Coder do?

Medical coding professionals provide a key step in the medical billing process. Every time a patient receives professional health care in a physician’s office, hospital outpatient facility or ambulatory surgical center (ASC), the provider must document the services provided. The Coder will abstract the information from the documentation, assign the appropriate codes, and create a claim to be paid, whether by a commercial payer, the patient, or CMS.

A medical billing coder analyzes patient charts and assigns the appropriate medical diagnosis codes and CPT medical billing codes. These codes are derived from ICD-9 codes and corresponding CPT treatment codes and any related CPT modifiers. Some medical billing and coding specialists obtain some type of certification from a recognized professional organization. In general the more certifications the greater the income potential. Proper coding is very important to getting fairly reimbursed.

Good coding complements the billing process and insures the provider is getting fairly compensated. Even if you want to stick strictly to medical billing, having a basic understanding of what the medical coding specialist does is important. If you are a biller, the more you can learn about coding, the more valuable you are to a practice or billing company. Most small practices don't have dedicated coders or billers - they multi-task and may perform limited coding functions in addition to billing.

The medical billing specialist really needs to know enough about coding to see when the CPT medical billing coding are not compatible with the ICD 9 codes. For smaller practices the provider may do their own coding and the medical billing specialist acts more to identify out of date codes so the provider can correct them. Most practices use a lot of the same CPT and ICD-9 codes so once you become familiar with the codes and medical billing modifiers, you've conquered the most difficult part. The most commonly used ones may be listed on the practice superbill.

For family or internal medicine practices, you may see a wider variety of codes and modifiers than for specialty providers. My medical billing company serves smaller practices that may need coding services, so we offer medical coding services to complement our billing services. Many medical billers prefer to stay strictly with medical billing services and that's great. But if you can become proficient in coding - even if you are not an expert - you're much more valuable to a provider.