2026 ICD-10-CM Diagnosis Code E08.21

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

Coding Guidelines

The diabetes mellitus codes are combination codes that include the type of diabetes mellitus, the body system affected, and the complications affecting that body system. As many codes within a particular category as are necessary to describe all of the complications of the disease may be used. They should be sequenced based on the reason for a particular encounter. Assign as many codes from categories E08 - E13 as needed to identify all of the associated conditions that the patient has.

Code Edits

The Medicare Code Editor (MCE) detects errors and inconsistencies in ICD-10-CM diagnosis coding that can affect Medicare claim validity. These Medicare code edits help medical coders and billing professionals determine when a diagnosis code is not appropriate as a principal diagnosis, does not meet coverage criteria. Use this list to verify whether a code is valid for Medicare billing and to avoid claim rejections or denials due to diagnosis coding issues.

MS-DRG Mapping for ICD-10-CM Code E08.21

Diagnosis-Related Groups (DRGs) are used to classify hospital cases for billing and healthcare management. They help standardize how hospitals and other providers are reimbursed for inpatient care. Patients are grouped based on their principal diagnosis into broader categories called Major Diagnostic Categories (MDCs).

Once assigned to a DRG, the hospital receives a set payment for the patient’s care, regardless of the actual services provided. This fixed rate is intended to cover the typical cost of treating patients within that group. The payment amount depends on the DRG's relative weight, which reflects the expected complexity and cost of care based on the severity of the patient’s condition.

Diagnostic related groups encourage healthcare providers to focus on quality and efficiency in patient care while managing costs effectively. The diagnosis code is present in the following groups for version MS-DRG V43.0 applicable from 10/01/2025 through 09/30/2026.

Convert E08.21 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

Patient Education

Diabetes

What is diabetes?

Diabetes, also known as diabetes mellitus, is a disease in which your blood glucose, or blood sugar, levels are too high. Glucose is your body's main source of energy. Your body can make glucose, but it also comes from the food you eat. Insulin is a hormone made by your pancreas. Insulin helps move glucose from your bloodstream into your cells, where it can be used for energy.

If you have diabetes, your body can't make insulin, can't use insulin as well as it should, or both. Too much glucose stays in your blood and doesn't reach your cells. This can cause glucose levels to get too high. Over time, high blood glucose levels can lead to serious health conditions. But you can take steps to manage your diabetes and try to prevent these health problems.

What are the types of diabetes?

There are different types of diabetes:

• Type 1 diabetes. If you have type 1 diabetes, your body makes little or no insulin. It happens when your immune system attacks and destroys the cells that produce insulin.
• Type 2 diabetes. This is the most common form of diabetes. If you have type 2 diabetes, your body may still be able to make insulin, but your cells don't respond well to insulin. They can't easily take up enough glucose from your blood.
• Gestational diabetes. This is a form of diabetes that develops during pregnancy. It happens when your body can't make the extra insulin it needs during pregnancy.

What causes diabetes?

The different types of diabetes have different causes:

• Researchers think type 1 diabetes is caused by genes and factors in the environment that might trigger the disease.
• Type 2 diabetes is caused by several factors, including lifestyle factors and genes. The lifestyle factors include not being physically active and being overweight or having obesity.
• Researchers think gestational diabetes is caused by the hormonal changes of pregnancy along with genetic and lifestyle factors.

Who is more likely to develop diabetes?

The different types of diabetes have different risk factors:

• You can develop type 1 diabetes at any age, but it most often starts in childhood. Having a parent or sibling with type 1 diabetes may increase your chance of developing it.
• You are at higher risk of developing type 2 diabetes if you:
• Are overweight or have obesity.
• Are over age 35. Children, teenagers, and younger adults can get diabetes, but it is more common in middle-aged and older adults.
• Have a family history of diabetes.
• Have prediabetes. This means that your blood glucose is higher than normal, but it's not high enough to be called diabetes.
• Had gestational diabetes.
• Have given birth to a baby weighing 9 pounds or more.
• Are African American, American Indian, Asian American, Hispanic/Latino, or Pacific Islander.
• Are not physically active.
• Have certain other health conditions, such as high blood pressure or polycystic ovary syndrome (PCOS).
• You are at higher risk of developing gestational diabetes if you:
• Are overweight or have obesity.
• Have a family history of diabetes.
• Had gestational diabetes in a previous pregnancy.
• Have given birth to a baby weighing 9 pounds or more.
• Have polycystic ovary syndrome (PCOS).
• Are African American, Hispanic/Latino, American Indian, Alaska Native, Native Hawaiian, or Pacific Islander.

What are the symptoms of diabetes?

The symptoms of diabetes may include:

• Feeling very thirsty
• Feeling very hungry
• Urinating (peeing) more often, including at night
• Fatigue
• Blurry vision
• Numbness or tingling in the feet or hands
• Sores that do not heal
• Losing weight without trying

But it's important to know that your symptoms may vary, depending on which type you have:

• The symptoms of type 1 diabetes usually come on quickly and can be severe.
• With type 2 diabetes, the symptoms often develop slowly, over several years. The symptoms can be so mild that you might not even notice them.
• Gestational diabetes often has no symptoms. If you do have symptoms, they may be mild. If you are pregnant, you will usually be screened for this condition between 24 and 28 weeks of pregnancy.

How is diabetes diagnosed?

To find out if you have diabetes, your health care provider will use one or more glucose blood tests. There are several types, including the A1C test.

What are the treatments for diabetes?

Treatment for diabetes involves managing your blood glucose levels:

• If you have type 1 diabetes, you will need to take daily doses of insulin, either by injection or through a special pump. Some people also need to take another type of diabetes medicine that works with insulin.
• If you have type 2 diabetes, you may be able to manage or even reverse it by making lifestyle changes. These include eating a healthy diet, staying at healthy weight, and getting regular physical activity. Some people also need to take diabetes medicines to manage their diabetes.
• If you have gestational diabetes, you may be able to lower your glucose levels by eating a healthy diet and getting regular exercise. But be sure to talk to your provider about your treatment options. Gestational diabetes usually goes away after you give birth. But you will have a higher risk of developing type 2 diabetes later.

Checking your blood glucose levels is also an important part of managing your diabetes. Ask your provider about the best way to check your blood glucose level and how often you should check it.

Can diabetes be prevented?

Type 1 diabetes can't be prevented.

You may be able to delay or prevent type 2 diabetes through the same lifestyle changes that are used to manage diabetes (eating a healthy diet, staying at a healthy weight, and getting regular physical activity). These lifestyle changes may also help prevent gestational diabetes.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

[Learn More in MedlinePlus]

Diabetic Kidney Problems

If you have diabetes, your blood glucose, or blood sugar, levels are too high. Over time, this can damage your kidneys. Your kidneys clean your blood. If they are damaged, waste and fluids build up in your blood instead of leaving your body.

Kidney damage from diabetes is called diabetic nephropathy. It begins long before you have symptoms. People with diabetes should get regular screenings for kidney disease. Tests include a urine test to detect protein in your urine and a blood test to show how well your kidneys are working.

If the damage continues, your kidneys could fail. In fact, diabetes is the most common cause of kidney failure in the United States. People with kidney failure need either dialysis or a kidney transplant.

You can slow down kidney damage or keep it from getting worse. Controlling your blood sugar and blood pressure, taking your medicines and not eating too much protein can help.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

[Learn More in MedlinePlus]

Code History

• FY 2026 - No Change, effective from 10/1/2025 through 9/30/2026
• FY 2025 - No Change, effective from 10/1/2024 through 9/30/2025
• FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
• FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
• FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
• FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
• FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
• FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
• FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
• FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
• FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.