B. E11.9, E66.01, Z68.41

Locate and Verify

Diabetes, Type 2

Diabetes mellitus codes are combination codes that include the type of diabetes mellitus, the body system affected, and the complications affecting that body system.

In the Alphabetic Index, look up Diabetic, type 2  E11.9. Then go to this code in the Tabular. We can verify the correct code as:

E11.9, Type 2 diabetes mellitus without complications

There is an instructional note at E11 that states:

“Use additional code to identify control using:

  • insulin (Z79.4)
  • oral antidiabetic drugs (Z79.84)
  • oral hypoglycemic drugs (Z79.84)”

However, the documentation does not indicate the patient uses insulin, oral antidiabetic drugs, or oral hypoglycemic drugs, so we can’t code it. There are other instructional notes that must be read as well before making the final code selection.

Morbid Obesity

Obesity puts a person at higher risk of developing diabetes and other conditions and should, therefore, be documented and reported. 

In the Alphabetic Index, look up Obesity, morbid  E66.01. Then go to this code in the Tabular. We can verify the correct code as:

E66.01, Morbid (severe) obesity due to excess calories

There is an instructional note at E66 that states:

“Use additional code to identify body mass index (BMI), if known (Z68.-).”

Body Mass Index

The documentation states that the dietician noted the patient’s BMI was 40.2.

When we go to Z68.- in the Tabular, we can see that our correct code is:

Z68.41, Body mass index [BMI] 40.0-44.9, adult 

The patient’s BMI provides the patient’s weight status and is classified according to severity.  

Body mass index (BMI) is typically used to specify the overweight severity: 

  • Overweight: BMI = 25.0-29.9
  • Obese: BMI = 30.0-39.9
  • Morbidly obese: BMI = 40+

FY 2021 ICD-10-CM Coding Guidelines

A change that has been made for FY 2021 is the use of brackets around “BMI”  in the code description ([BMI] instead of parentheses (BMI). The ICD-10-CM Official Guidelines for Coding and Reporting state that brackets in the Tabular List “enclose synonyms, alternative wording, or explanatory phrases.” Parentheses, on the other hand “enclose supplementary words that may be present or absent in the statement of a disease or procedure without affecting the code number to which it is assigned.”

The 2021 coding guidelines also state that code assignment for BMI may be based on medical record documentation from clinicians who are not the patient’s provider since this information is typically documented by other clinicians involved in the care of the patient, such as a dietician. The associated diagnosis, such as overweight and obesity, must be documented by the patient’s provider. If there is conflicting information in the record, the attending provider should be queried for clarification.

BMI codes are used in conjunction with codes for any associated condition (i.e., E40-E46, E66.-, D68, R64).

Incorrect Answers

A, C, and D are incorrect.

A. E10.9, E66.01, Z68.41. E10.9 refers to Type 1 diabetes mellitus without complications. 

C. E08.9, E66.9. E08.9 refers to Diabetes mellitus due to underlying condition without complications. E66.9 refers to Obesity, unspecified. 

D. E10.9, E66.09, Z79.4. E10.9 refers to Type 1 diabetes mellitus without complications. E66.09 refers to Other obesity due to excess calories. Z79.4 refers to Long term (current) use of insulin.

Final Thoughts

Something to keep in mind here that may help you find the answers more quickly as you go through a timed exam:

Look at the answers before you read the question.

  • At quick glance, I can see that options A and D both have E10.9 listed; A and B both have E66.01 and Z68.41; and only option D has code Z79.4.
  • I can also see that option C is the only one that does not have a Z code.
  • And because I know  my mnemonics, I can see that the E codes listed are found in the chapter on Endocrine, Nutritional, and Metabolic Diseases (E00-D89). In fact, I may have had a lot of coding practice up to this point and know that E10.9, E11.9, and E08.9 are diabetes mellitus codes.
  • I may even know that Z79.4 is the code for long-term use of insulin.

Whatever I can gather from the answers quickly before reading the question can really speed up the process.

Now, when I read the question/documentation, I can see that, yes, the patient has type 2 diabetes mellitus, is morbidly obese due to overeating (excess calories), and has a BMI of 40.2. There is no mention of insulin use.

The guidelines and conventions tell me that:

  • A BMI code (Z68.41) should only be reported as a secondary code after the obesity code (E66.01)
  • A clinician involved in the patient’s care, such as a dietician, may document the BMI, but the associated diagnosis (obesity) must be documented by the patient’s provider. This has been done in this case, so we may code it. Otherwise, a query should be sent to the provider.