ICD-10 Explained: A Comprehensive Guide to Medical Coding

Medical coding has become a non-negotiable aspect of modern healthcare. Over the years, healthcare regulatory bodies like the American Medical Association (AMA) and CMS(Centre for Medicare and Medicaid Services) have developed and published different coding systems to serve the various aspects of healthcare in the USA. However, for healthcare systems around the world, a uniform coding system called the International Classification of Diseases or ICD by WHO is the go-to guide for medical codes. ICD forms the basis for the medical coding systems being used in the USA. Since its inception, ICD codes have undergone tremendous changes and every updated version of ICD codes is published for the perusal of medical providers from time to time. The ICD-10 is the tenth edition of this coding system. This article aims to give you a detailed idea about what is included and excluded in this tenth edition of the ICD, how it helps medical communities across the world interpret and record various diseases and what its future is.

What is ICD 10? International Classification of Diseases 10th Revision

The International Classification of Diseases (ICD) is a set of medical codes developed and updated by the WHO to track and classify diseases and diagnoses among the world’s population. ICD 10 is the 10th edition of the list of codes released by the WHO. ICD codes also help determine the cause of death among the world’s population. Around the world, ICD-10 codes and their variations are used for patient care, medical billing, as part of the revenue cycle management process. This article aims to illuminate the conception, importance and use cases of ICD-10.

A Brief History of ICD

In the early 1800s, the International Statistical Society developed the first International Classification of Diseases to consolidate causes of death and illness among the world’s population. This system was based on the Bertillon Classification of Causes of Death, developed by the French statistician Jacques Bertillon. In 1898, various countries started adopting this system to record illnesses and deaths. Eventually, Bertillon’s system was known as the International List of Causes of Death which later evolved to the International Classification of Diseases or ICD. In 1948, the World Health Organization undertook the responsibility of updating and publishing the ICD. 

What is new in ICD-10 CM?

Morbidity and mortality are two major aspects of medical diagnosis. Morbidity defines the state of diseases while mortality defines the cause of death. The ICD-9-CM was used by hospitals and other health care facilities, particularly for reporting morbidity (the ICD-10 was used to report mortality data). The ICD-9-CM was replaced by the ICD-10-CM in 2015 and the latter by the ICD-11-CM in 2022. The following modifications were made in ICD-10 CM.

Specificity and Detail

Granularity: ICD-10 allows for much more detailed coding, which includes aspects such as laterality (indicating whether a condition affects the left or right side of the body), severity, and episode of care. This level of detail was largely absent in ICD-9.

Combination Codes: ICD-10 supports combination codes that can express multiple elements of a diagnosis in one code, enhancing clarity and reducing the risk of errors.

Flexibility and Expansion

New Code Creation: ICD-10 provides greater flexibility for adding new codes as medical knowledge evolves. This is crucial as new diseases and conditions emerge, which was a limitation in the outdated ICD-9 system.

Clinical Modifications

Clinical Modifications: Both systems include Clinical Modifications (CM) for use across U.S. healthcare settings. However, ICD-10-CM's expanded code set allows for more precise diagnosis coding compared to ICD-9-CM.

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ICD-9 Vs ICD-10 (Coding Nomenclature)

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Where is ICD 10 Used?

The ICD is adopted by several healthcare systems everywhere, partially or fully. A variation of ICD, the ICD-10 CM is used in the US healthcare system. The US Department of Health and Human Services felt that the ICD lacked detailed clinical information on various diseases. They developed a system, ICD-9 CM where CM stood for Clinical Modification. ICD-CM codes provided detailed information and explanations for morbidities and mortalities. The ICD -9 CM was replaced by ICD-10 CM in 2015. 

ICD-10, HCPCS, CPT and DRG Codes - Are they similar?

ICD-10 codes serve similar purposes as the HCPCS, CPT coding families. However, the ICD was developed to track morbidity and mortality in the world’s population as opposed to the earlier coding systems which were specifically developed for billing and insurance purposes in the US healthcare systems. 

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HCPCS

The Healthcare Common Procedural Coding System (HCPCS) is formulated by the Centre for Medicare and Medicaid Services (CMS) to define outpatient procedures for Medicare beneficiaries.  HCPCS codes help hospitals and other healthcare providers record outpatient procedures for Medicare patients, thus facilitating a smooth billing process.

CPT

Current procedural terminologies are codes used by hospitals and other medical institutions to define any regular medical procedure. The AMA (American Medical Association) publishes and maintains this code set. CPT codes are further divided into categories. The first category, or Category I, covers general procedures conducted in a physician’s office. Category II codes cover performance measures and quality indicators for patient care. Category III codes are used to track usage of new services and provide documentation to the FDA. 

DRG

The codes belonging to Diagnosis-Related Groups (DRG) indicate the different in-patient services rendered to Medicare and Medicaid patients. Hospitals and private healthcare practitioners use this system to classify the patients enrolled for in-patient procedures.

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With the recent developments in the healthcare industry and with numerous new treatments being discovered every day, categorizing diseases, symptoms, and diagnoses into medical codes has become the need of the hour for hospitals and healthcare providers. As coding involves processing vast amounts of data, having an automated system helps. CombineHealth’s AI medical coding and billing software can help hospitals and private agencies improve efficiency and reduce administrative workload. 

Use Cases of ICD-10 Coding System

The ICD coding system is used in all walks of the healthcare industry. From billing to patient care, it is used by all medical personnel to ensure efficacy in patient care and revenue management process. Here are a few practical examples of how ICD-10 CM codes benefit healthcare professionals.

Hospital billing

ICD-10 CM codes are used to identify and classify various types of diseases and their diagnoses. This makes medical coding in the healthcare industry easier.

Processing claims

Insurance providers as well as medical professionals are familiar with ICD-10 coding system. Hence, it is used by both parties to expedite the medical claims process.

Medical data collection

Converting medical records into codes requires coders to process huge amounts of medical data. With the advent of AI-based coding systems like CombineHealth’s software, this task has become hassle-free. With ICD-10 codes, it becomes easier to look for data for research purposes.

What are the complications of using ICD-10 CM?

Although the ICD system was introduced to make it easier for those in need to find, classify and use codes for medical diagnosis, there are times when it can go completely wrong. The ICD 10 CM coding system has a few flaws that are noted below.

1. Incorrect coding: The US healthcare system makes use of coding systems other than the ICD for various reasons and purposes. In most cases, it so happens that ICD 10 CM codes do not match with those in ICD 9. This can lead to billing errors and claim denials due to incorrect coding practices. Hence, it is essential to employ a robust mechanism to cross-check codes. 

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2. Mis-aligned definitions: The definition of diseases in ICD 9 are different than those in ICD-10. This can lead to misjudgement while recording medical procedures.

Conclusion

To summarize, the ICD-10 CM included new medical codes for diseases that were not included in ICD-9. It included modifications in code structure and length - the ICD-10 codes include 3-7 alphanumeric characters as opposed to ICD-9 codes which include 2-5 numeric characters. This expansion allowed specificity and granularity in recording causes of deaths and diseases. The ICD-10 codes provide details such as laterality (right vs left) , severity and the specific anatomical site affected. The total number of codes increased to 68000 from the 13000 codes in ICD-9.  The ICD-10 also allows for future modifications for newly found medical data. The granularity of ICD-10 allows improved data quality, thus enabling healthcare providers to document accurate diagnoses for medical billing and insurance claims. With its advanced AI workforce, CombineHealth is transforming medical coding. AI-powered medical coders like Amy help analyze medical records, including doctor notes, test descriptions, medical history, etc., and automatically assign the appropriate ICD-10 and CPT codes based on the documented diagnoses and procedures.

FAQs

What are the challenges faced by healthcare systems while implementing ICD-10 coding system? How are they solved?

Some of the common issues healthcare professionals encounter are coding errors and mis-aligned definitions.

How does CombineHealth help in medical coding?

CombineHealth’s AI-powered coding system can process 1000s of pages in an hour. This includes an extensive amount of data. Billing processes can be expedited when coding is automated with AI powered software.

Where can I find ICD codes?

• Medical records: ICD codes may be listed under "Problems" or "Diagnoses". 
• Medical bills or provider letters: ICD-10 codes are often printed under or after the "Diagnosis" heading. 
• Explanation of benefits (EOB) statements: ICD codes may be included in EOB statements from your insurer.

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