International Classification of Diseases facts for kids

Kids Encyclopedia Facts

The International Classification of Diseases (ICD) is a super important tool used all over the world. It helps doctors and health experts understand and classify different diseases and health problems. Think of it like a giant dictionary or a special codebook for illnesses.

The World Health Organization (WHO) creates and updates the ICD. The WHO is a big group that helps countries work together on health issues. The ICD helps everyone speak the same language when talking about health. It gives a special code, up to six characters long, to every health condition. This way, similar diseases are grouped together.

Doctors and hospitals use the ICD for many things. It helps them keep track of how many people get sick or pass away from certain diseases. It also helps with health insurance and making sure patients get the right care. The main goal is to make sure health information can be compared between different countries. This helps us learn more about health around the globe.

The ICD is updated regularly. The newest version is called ICD-11. It was approved in 2019 and officially started being used on January 1, 2022.

The ICD is part of a "family" of health classifications from the WHO. This family also includes the International Classification of Functioning, Disability and Health (ICF), which looks at how health conditions affect what people can do. Another one is the International Classification of Health Interventions (ICHI), which classifies different medical treatments and procedures.

The full name of the ICD is the International Statistical Classification of Diseases and Related Health Problems. But most people just call it the ICD.

In some countries, like the United States, another book called the Diagnostic and Statistical Manual of Mental Disorders (DSM) is often used for classifying mental health conditions.

How the ICD Started
ICD Versions Over Time
ICD Use in the United States
Classifying Mental Health
See also

How the ICD Started

The idea for the ICD goes way back! In 1860, a famous nurse named Florence Nightingale suggested a way to collect hospital data. This helped lead to the first system for tracking health information.

Then, in 1893, a French doctor named Jacques Bertillon created a system to classify causes of death. Many countries started using his system. It grouped diseases by general types or by specific body parts.

Over time, this system grew. It started with 44 categories and expanded to 161. In 1898, the American Public Health Association (APHA) suggested that countries like Canada, Mexico, and the United States should use it too. They also said the system should be updated every 10 years to keep up with new medical discoveries. The first international meeting to update it happened in 1900.

At first, the classification system was just one small book. It had a list of diseases and an index to find them.

ICD Versions Over Time

The ICD has changed a lot over the years to become what it is today.

ICD-6: A Big Step Forward

The ICD-6 came out in 1949. This was a very important version because it was the first one designed to track not just deaths, but also how many people were sick (called morbidity). Because of this, its name changed from "International List of Causes of Death" to "International Statistical Classification of Diseases."

This version also separated injuries from their causes. For the first time, it included a section for mental disorders.

ICD-7 and ICD-8: Small Updates

The ICD-7 was released in 1955. It mostly made small changes and fixed errors.

The ICD-8 came out in 1965. This update was a bit bigger, but it kept the main way diseases were classified. It still tried to group diseases by their cause whenever possible.

During these years, more and more hospitals started using the ICD to organize their patient records. Some countries even made their own versions of the ICD to add more details for hospital use.

ICDA-8 in the United States

In the US, experts looked at the ICD-8. They wanted more details for coding hospital and sickness data. So, they created the "International Classification of Diseases, Adapted" (ICDA). In 1968, the US Public Health Service published ICDA-8. It became the main system for coding health information in the United States.

ICD-9: More Detail and Flexibility

The ICD-9 was created in 1975 and published in 1978. People wanted more details in the classification. They also wanted it to be more useful for evaluating medical care.

The ICD-9 kept the basic structure but added a lot more detail. It had new four-digit subcategories and even some optional five-digit ones. This made it more flexible for different users.

One new feature was the 'dagger and asterisk system'. This allowed doctors to classify a condition by both the main disease and how it showed up in a specific body part. This system is still used in the ICD-10.

The ICD-9 was eventually replaced by ICD-10. Because ICD-10 was so much bigger, it's hard to directly change ICD-9 data into ICD-10 data.

ICD-9-CM in the United States

The International Classification of Diseases, Clinical Modification (ICD-9-CM) was a special version created for the United States. It was used to assign codes for diagnoses and procedures in hospitals and doctor's offices. ICD-9-CM was based on ICD-9 but had even more details for tracking sickness. It was updated every year on October 1st.

It had three parts:

Volumes 1 and 2 contained codes for diagnoses.
Volume 3 contained codes for surgical, diagnostic, and treatment procedures.

ICD-10: A Huge Expansion

Work on ICD-10 started in 1983 and was approved in 1990. It began being used in WHO member countries in 1994. This version was a massive upgrade! It has over 55,000 different codes, which is a lot more than the 17,000 codes in ICD-9. This allowed for tracking many new diagnoses and procedures.

Most of the world quickly adopted ICD-10. The WHO provides many online tools to help people use it. Some countries, like Australia and Canada, made their own versions, such as "ICD-10-AM" and "ICD-10-CA."

ICD-10-CM in the United States

The United States was slower to adopt ICD-10. For a long time, the US used ICD-9-CM for health insurance claims. In 1999, ICD-10 was used for reporting deaths, but ICD-9-CM was still used for sickness.

The US created its own clinical modifications of ICD-10:

ICD-10-CM: For diagnosis codes.
ICD-10-PCS: For procedure codes.

The US government planned to switch to ICD-10-CM in 2013, but it was delayed several times. The US finally started requiring the use of ICD-10-CM for most clinical encounters on October 1, 2015.

ICD-10-CM included many improvements:

More information for doctor's office visits.
More detailed injury codes.
New codes that combine a diagnosis and a symptom, so fewer codes are needed.
Added sixth and seventh digits for more specific classification.
Codes that specify left or right side of the body.

ICD-10-CA in Canada

ICD-10-CA is Canada's version of ICD-10. It was developed by the Canadian Institute for Health Information. It's used for classifying sickness in Canada and includes conditions that aren't diseases but can affect health, like lifestyle factors.

ICD-11: The Latest Version

The icon for the ICD-11 Beta browser.

The ICD-11 is the newest and largest version of the International Classification of Diseases. It's almost five times bigger than ICD-10! It took over 10 years to create, with help from more than 300 experts from 55 countries. A stable version was released in 2018 and officially approved by the WHO in 2019.

For ICD-11, the WHO decided to have a main "Foundation Component" that includes all ICD items. From this, different versions can be made. The main version, called ICD-11 MMS (Mortality and Morbidity Statistics), is what people usually mean when they say "ICD-11."

ICD-11 comes with many tools to help countries switch over, including guides, a translation tool, and a coding tool. All these tools are available online.

ICD-11 officially started on January 1, 2022. However, the WHO knows it will take time for many countries to fully adopt it. In the United States, it might not be fully used until 2025 or even 2027.

ICD Use in the United States

The United States has a long history of adapting the ICD for its own needs.

In 1962, the US Public Health Service created ICDA (International Classification of Diseases, Adapted) to help hospitals index records.
Later, they published ICDA-8 for national health statistics.
Then came ICD-9-CM, which hospitals and other healthcare places used to describe patient conditions.

The US government planned to switch to ICD-10 in 2010, but it was delayed twice. The US finally started using ICD-10-CM for most health encounters on October 1, 2015.

Here's a quick look at when different ICD versions were used for causes of death in the US:

ICD-1: 1900
ICD-2: 1910
ICD-3: 1921
ICD-4: 1930
ICD-5: 1939
ICD-6: 1949
ICD-7: 1958
ICDA-8: 1968
ICD-9-CM: 1979
ICD-10-CM: 1999

The Centers for Disease Control and Prevention (CDC) uses the ICD to track causes of death in the US.

Classifying Mental Health

The ICD has a special section for classifying mental and behavioral disorders. This section has grown alongside another important manual, the Diagnostic and Statistical Manual of Mental Disorders (DSM), used by the American Psychiatric Association. Both manuals aim to use similar ways to classify mental health conditions.

The WHO is updating these classifications for ICD-11. Experts are working together to guide these changes. The goal is to make sure the classifications are helpful and accurate for doctors and patients around the world.

A study of psychiatrists in 66 countries found that they often used ICD-10 for diagnosing patients. They found the DSM-IV more useful for research. Even though many mental health professionals in the US might not realize it, the ICD is actually the official system there.