Primary Care Coding Alert

Question: When can I use a combination code for diabetes and its complication? For example, if type 2 diabetes and retinopathy are both mentioned in the medical report, can I assume a causal relationship even if the provider has not documented “with” or “due to” in the note?

AAPC Forum Participant

Answer: ICD-10 guidelines tell you that “a combination code is a single code used to classify: two diagnoses, or a diagnosis with an associated secondary process (manifestation) [and/or a] diagnosis with an associated complication. Combination codes are identified by referring to subterm entries in the Alphabetic Index and by reading the inclusion and exclusion notes in the Tabular List. Assign only the combination code when that code fully identifies the diagnostic conditions involved or when the Alphabetic Index so directs.”

You will find numerous conditions listed in the index under type 2 diabetes that are linked by the word “with,” which tells you that a combination code exists for both conditions when they co-exist. In your particular case, there are several codes to choose from dependent on the laterality, kind, and severity of retinopathy the patient has, including E11.31- (Type 2 diabetes mellitus with unspecified diabetic retinopathy), that you could use if that is what your provider has documented.

But provider documentation is key to code choice in these situations. You cannot — and should not — assume a causal relationship if the provider has not documented that the retinopathy is associated with, or is due to, the patient’s diabetes. If in doubt, you should ask your provider.