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Coding Alert – ICD-10-CM
Coding Tips for Diabetes Mellitus

Diabetes Mellitus diagnosis codes are no longer classified as controlled or uncontrolled as previously defined in ICD-9-CM.  Instead ICD-10-CM classifies inadequately controlled, out of control and poorly controlled diabetes mellitus by type of hyperglycemia.

The ICD-10-CM codes have been expanded to reflect manifestations and complications of the disease by using fourth and fifth characters (combination codes) rather than by using an additional code to identify the manifestation. For example, E11.22 reports a patient with type 2 diabetes mellitus with diabetic chronic kidney disease.

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Important Coding Reminders

  • Use an additional code to identify any insulin, Z79.4
  • If diabetes mellitus type is not documented, the default is Type 2 Diabetes Mellitus
  • All conditions must be documented to assign the combined codes.
  • As many codes within a particular category as needed to describe all the complications of the disease can be used. They should be sequenced based on the reason for a particular encounter.
  • Diabetes in pregnancy: include a final character indicating the trimester of pregnancy.
  • If a patient with gestational diabetes is treated with both diet and insulin, only the code for insulin controlled is required.
  • The sequencing of the secondary diabetes codes in relationship to codes for the cause for the diabetes is based on the Tabular List instructions for categories E08 and E09 and E13.
  • Understand that secondary diabetes mellitus is always caused by another condition or event.
  • Over and under-dosing of insulin due to insulin malfunction should be sequenced as follows –
    • Mechanical complication
    • Over / under-dosing
    • Type of diabetes
    • Associated complications with under-dosing

Important Documentation Reminders

  • Specify Type 1 or Type 2
  • Controlled or uncontrolled
  • Document the degree of control
  • Specify insulin use
  • Manifestations or complication
  • Specify complications to a very specific degree

If you have coding questions, contact your Provider Coordinator. We’re happy to help.


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