A quick reference guide to assist with accurate, complete documentation and coding that reflects the true nature of a patient’s current health status at the highest level of specificity. Per ICD-10 official guidelines for reporting and coding, “The importance of consistent, complete documentation in the medical record cannot be overemphasized. Without such documentation, accurate coding cannot be achieved.”  

One of the most important endocrine organs is the pancreas, which secretes insulin and regulates glucose levels within the body. Diabetes mellitus describes conditions in which the body does not produce any insulin at all (Type 1) or it is unable to synthesize the insulin produced (Type 2). In addition, ICD-10-CM classifies several other distinct types of diabetes, depending upon the underlying cause. In addition to the expanded number of categories of diabetes codes, the subclassification of each type of diabetic disorder is much more detailed. Combination codes describe common associated conditions, along with severity classifications.

Documentation & Coding Tips 

Documentation needs to be clear and detailed using the following terms to allow accurate ICD10 code selection. 

Specificity:

• Control: There is no default code for diabetes mellitus documented only as “uncontrolled.” The provider must indicate whether the diabetic patient is hypoglycemic or hyperglycemic to determine the appropriate code. 
• Type: Type 1, Type 1.5 (LADA: latent autoimmune diabetes in adults), or Type 2 
• Secondary cause: identify cause (drug or other chemical-induced, other underlying condition)  

Complications: Assign as many codes from categories E08 – E13 as needed to identify all the associated conditions/complications that the patient has related to their diabetes (See causal relationship notes below). 

• Microvascular (small blood vessel) complications: retinopathy, nephropathy, neuropathy 
• Macrovascular complications: CAD, PAD, PVD, MI, cardiomyopathy, CVA, TIA 

Treatment: (medication, diet, exercise, insulin pump, or a combination) and current response to treatment.  

Diabetes in Pregnancy & Gestational Diabetes 

ICD 10 Code: O24.xxxx

• Diabetes mellitus in pregnancy, childbirth, and the puerperium 
• The codes in this category are classified based on the type of diabetes (e.g., Type 1, Type 2, gestational) and by the timing of the diabetes (e.g., during a pregnancy, childbirth, or postpartum). 

Complications Due to Insulin Pump Malfunction 

ICD 10 Code:  T85.6xxx + T38.3X6x + Diabetes Type + associated complications from underdosing

• Underdose of insulin due to insulin pump failure 
• An underdose of insulin due to an insulin pump failure should be assigned to a code from subcategory T85.6, Mechanical complication of other specified internal and external prosthetic devices, implants, and grafts, that specifies the type of pump malfunction, as the first-listed code, followed by code T38.3X6-, Underdosing of insulin and oral hypoglycemic [antidiabetic] drugs.  Additional codes for the type of diabetes mellitus and any associated complications due to the underdosing should also be assigned. 

IDC 10 Code: T85.6xxx + T38.3X1x

• Overdose of insulin due to insulin pump failure 
• The first-listed code for an encounter due to an insulin pump malfunction resulting in an overdose of insulin should also be T85.6-, Mechanical complication of other specified internal and external prosthetic devices, implants, and grafts, followed by code T38.3X1-, Poisoning by insulin and oral hypoglycemic [antidiabetic] drugs, accidental (unintentional). 

Diabetes Medication Coding

IDC 10 Code: Z79.4

• Long-term (current) use of insulin
• Should not be assigned if insulin is given temporarily to bring a type 2 patient’s blood sugar under control during an encounter.

IDC 10 Code: Z79.84

• Long-term (current) use of oral hypoglycemic drugs

IDC 10 Code: Z79.85

• Long-term (current) use of injectable non-insulin antidiabetic drugs 

Causal Relationship Notes: 

The word “with” or “in” should be interpreted to mean “associated with” or “due to” when it appears in a code title, the Alphabetic Index (either under a main term or subterm), or an instructional note in the Tabular List. The classification presumes a causal relationship between the two conditions linked by these terms in the Alphabetic Index or Tabular List.  

These conditions should be coded as related even in the absence of provider documentation explicitly linking them, unless the documentation clearly states the conditions are unrelated or when another guideline exists that specifically requires a documented linkage between two conditions (e.g., sepsis guideline for “acute organ dysfunction that is not clearly associated with the sepsis”).  

For conditions not specifically linked by these relational terms in the classification or when a guideline requires that a linkage between two conditions be explicitly documented, provider documentation must link the conditions in order to code them as related.  

The word “with” in the Alphabetic Index is sequenced immediately following the main term or subterm, not in alphabetical order.

References:

CDC Prevent Diabetes Complications

Optum EncoderPro.com for Payers

ICD-10-CM Official Guidelines for Coding and Reporting FY 2023 - UPDATED April 1, 2023  (PDF)