Patients who have diabetes often have one or more complications that require your extra attention, and these added problems can have a significant effect on the E&M level you bill. Use these steps for diabetes diagnosis coding to ensure that your ICD-9-CM codes justify the services you bill.
Use the correct digits
Determine the fourth digit for 250.xx (diabetes mellitus) according to the type of diabetic complication the patient has (1 for ketoacidosis, 4 for renal conditions, 6 for neurological involvement, etc.). You should code only the complication relevant to the services you render during the visit.
Use V codes
Just as fourth and fifth digits paint a more complete picture of a patient's diabetes, V codes are also important for telling the carrier the whole story. Assign V58.67 as a secondary code for patients who take insulin.