CORRECTLY CODING: DIABETES MELLITUS
When selecting International Classification of Diseases, Tenth Revision (ICD-10), diagnostic codes, accuracy is important when
describing the patient’s true health. A joint effort between the healthcare provider and the coder/biller is essential to achieve
complete and accurate documentation, code assignment, and reporting of diagnoses and procedures.
Diabetes mellitus is one of the most inaccurately coded chronic conditions. Many billers/coders/providers are missing
opportunities to show which patients are sicker and are at a higher risk. The prevalence of diabetes mellitus and the complexity of
diabetes coding require a solid understanding of the ICD-10 coding guidelines to ensure accurate code assignment.
These diagnosis codes are also used in determining the eligible population for the Comprehensive Diabetes Care quality measure
and the threshold the member is held to in order to be in control for the Controlling High Blood Pressure quality measure.
ICD-10 Category E11* Diabetes Mellitus: Tips on How to Code using ICD-10 Codes
Diabetes Mellitus is an HCC (Hierarchical Condition Category)
The diabetes mellitus codes are combination codes that include:
1. The type of diabetes mellitus
2. The body system(s) affected
3. The complications affecting the body system(s)
When coding diabetes mellitus, you should use as many codes from categories E08-E13* as necessary to describe all of the
complications and associated conditions of the disease. These categories are listed below:
ICD-10 Code Category ICD-10 Description Note:
E08* Diabetes mellitus due to underlying condition Code first the underlying condition
Use additional code to identify any insulin use
E09* Drug or chemical induced diabetes mellitus Code first poisoning due to drug or toxin, if applicable
Use additional code for adverse effect, if applicable, to identify drug
Use additional code to identify any insulin use
E10* Type 1 diabetes mellitus No additional code needed to identify insulin use
E11* Type 2 diabetes mellitus Use additional code to identify any insulin use
E13* Other specified diabetes mellitus Use additional code to identify any insulin use
If a patient has not previously been diagnosed with diabetes and is being seen for a screening, it is not appropriate to assign a diabetic
diagnosis. You would assign ICD-10 code Z13.1, Encounter for screening for diabetes mellitus. This code can be found under “Screening”
in the Alphabetical Index of the ICD-10 book.
If a member has been diagnosed with prediabetes, or has had a previous diagnosis of diabetes and the disease is now considered
latent or dormant (per the provider’s documentation) the ICD-10 code R73.09, Other abnormal glucose, should be assigned.
This code can be found under “Diabetes” and then “latent,” or under “Abnormal” and then “glucose” in the Alphabetical Index of the
ICD-10 book.
Diabetes codes are no longer classified as controlled or uncontrolled. Classifications such as inadequately controlled, out of control,
poorly controlled, and uncontrolled are coded to Diabetes, by type, with hyperglycemia in the ICD-10 book.
In ICD-10, there is no instructional note found under diabetes mellitus codes requiring an additional code to identify the
manifestation because it is already part of the code description. However, specific diabetes codes require additional codes in order to
identify the manifestation further, such as diabetes with foot ulcer to identify the site of the ulcer, or diabetes with chronic kidney
disease to identify the stage of chronic kidney disease.
In order to link a manifestation/complication to the diabetes mellitus the documentation must clearly show that there is a causal effect
of the disease to the associated manifestation. A coder cannot assume that there is a causal relationship between two diagnoses.
One diagnosis code MUST be clearly documented in the medical record as being directly related to the other.
Examples: • Diabetic Nephropathy • CKD Due to DM • PVD Due to DM • PAD Due to DM • Diabetic Neuropathy
• Peripheral Neuropathy Due to DM • Etiology of Neuropathy is DM • Diabetic Retinopathy • Diabetic Cataract • Diabetic Macular Edema
The type of diabetes mellitus should always be clearly documented in the medical record for each date of service; however, if the type
of diabetes mellitus is not documented in the medical record the default ICD-10 diagnosis code is E11.*, Type 2 diabetes mellitus.
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