Primary Care Coding Alert

Specify obesity classes with new codes.

With more than 250 new diagnosis codes, the 2025 ICD-10 code set affects almost every category. On Oct. 1, 2024, the Centers for Medicare & Medicaid Services (CMS) updated the code set, and as a primary care coder, you will want to take note, as multiple additions and revisions will alter your code selections.

Find out what changes primary care coders should prepare for in FY 2025.

Boost Your BMI and Obesity Code Knowledge

The 2025 ICD-10 code set features new codes tied to the different obesity classes. You’ll assign the following codes from the E66.8- (Other obesity) code subcategory depending on the obesity class diagnosis:

• E66.811 (Obesity, class 1)
• E66.812 (Obesity, class 2)
• E66.813 (Obesity, class 3)

Class 1 obesity is for a body mass index (BMI) range of 30 to 34.9, class 2 obesity covers the 35 to 39.9 BMI range, and class 3 obesity is for a BMI of 40 or more.

Several factors can impact a patient’s health, and obesity is one of them. For instance, the condition negatively affects the lung volume, which means the patient may not always be able to get a full breath or achieve full lung volume. This will lead to breathing problems.

Pediatric coding: While many children may have obesity, the standard BMI scale may be inaccurate to evaluate a child’s weight. While “severe obesity” in children and teens could only be captured by Z68.54 (Body mass index [BMI] pediatric, greater than or equal to 95th percentile for age) before October 2024, the American Academy of Pediatrics prefers to use an expanded definition of “severe obesity” that mimics the three adult obesity classes to better represent the problem.

Thus, the 2025 ICD-10 code set features a revision and new codes related to pediatric BMI numbers. Effective Oct, 1, 2024, Z68.54’s descriptor contains greater detail regarding the BMI of a pediatric patient. Compare the Z68.54 descriptors below between the 2024 and 2025 code sets:

• 2024: Body mass index [BMI] pediatric, greater than or equal to 95th percentile for age
• 2025: Body mass index [BMI] pediatric, 95th percentile for age to less than 120% of the 95th percentile for age

“The 2024 Z68.54 descriptor is considered ‘obesity,’ while the 2025 descriptor is similar to ‘severe obesity’ or class 1 obesity,” says Carol Pohlig, BSN, RN, CPC, manager of coding and education in the department of medicine at the Hospital of the University of Pennsylvania in Philadelphia.

At the same time, the 2025 ICD-10 code set adds more pediatric BMI codes that providers may document during evaluation and management (E/M) visits:

• Z68.55 (Body mass index [BMI] pediatric, 120% of the 95th percentile for age to less than 140% of the 95th percentile for age)
• Z68.56 (Body mass index [BMI] pediatric, greater than or equal to 140% of the 95th percentile for age)

Code Z68.55 is similar to class 2 obesity and Z68.56 is similar to class 3 obesity, according to Pohlig.

Remember: Even though an 18-year-old is legally considered an adult, the Body Mass Index (BMI) (Z68) section of ICD-10 explains that BMI adult codes are for patients 20 years of age or older and BMI pediatric codes are for patients ages 2 to 19.

Eating Disorder Diagnosis Codes Get More Specific

There are also a number of additions to the 2025 ICD-10 code set that affect how you report certain codes from chapter 5: Mental and Behavioral Disorders. For starters, code F50.01 (Anorexia nervosa, restricting type), a currently existing code, will be converted to a parent code.

Then, ICD-10 will expand this set to include the following new codes:

• F50.010 (Anorexia nervosa, restricting type, mild)
• F50.011 (Anorexia nervosa, restricting type, moderate)
• F50.012 (Anorexia nervosa, restricting type, severe)
• F50.013 (Anorexia nervosa, restricting type, extreme)
• F50.014 (Anorexia nervosa, restricting type, in remission)
• F50.019 (Anorexia nervosa, restricting type, unspecified)

ICD-10 2025 also converts the following already existing codes to parents:

• F50.02 (Anorexia nervosa, binge eating/purging type)
• F50.2 (Bulimia nervosa)
• F50.81 (Binge eating disorder)

Beneath each of the parent codes, you will now have 5th or 6th character options like those listed for F50.01. Note that, while these descriptions are general, additional information listed under each helps determine whether a case fits in the mild, moderate, severe, or extreme category. For the F50.01- and F50.02- families, severity will be determined based on the patient’s BMI. For the F50.2- and F50.81- families, severity will be determined by episodes of binging or purging per week.

Prepare for New SDOH Code Options

In recent years, CMS has added social determinants of health (SDOH) codes to the ICD-10 code set to gather information regarding external factors that affect the patient’s health status or reasons for seeking healthcare. The data collected from the SDOH Z codes can help healthcare move toward better equity in delivery and research.

The 2025 ICD-10 code set is no different. Effective Oct, 1, 2024, Z59.7- (Insufficient social insurance and welfare support) is converted to a parent code. This code subcategory adds new codes for providers to specify SDOH factors that affect the patient’s ability to receive care for their conditions.

You’ll assign Z59.71 (Insufficient health insurance coverage) if the documentation includes information that the patient doesn’t have adequate (or any) health insurance to ensure care or treatment. Code Z59.72 (Insufficient welfare support) will also be available for you to use in October 2024 if the information is included in the patient’s record.

Mike Shaughnessy, BA, CPC, Development Editor, AAPC and Chris Boucher, MS, CPC, Senior Development Editor, AAPC