Coding Diabetes Mellitus in ICD-10-CM
By Karen M. Kostick
ICD-10-CM diabetes codes complement present medical science—separate type 1 and type 2 diabetes category codes and body system combination codes represent a major improvement over ICD-9-CM. Diabetes mellitus codes are no longer classified as controlled or uncontrolled. Instead ICD-10-CM classifies inadequately controlled, out of control, and poorly controlled diabetes mellitus by type with hyperglycemia.
ICD-10-CM diabetes codes are combination codes that include the type of diabetes mellitus, body system affected, and the complications affecting that body system. The following examples apply ICD-10-CM chapter 4, “Diabetes mellitus E08-E13” tabular list instructions and illustrate diabetes mellitus code combinations and code specificity.
ICD-10-CM Diabetes Mellitus Coding Examples
ICD-10-CM diabetes codes are combinations codes that include the type of diabetes mellitus, body system affected, and the complications affecting that body system.
Diagnosis: A patient is seen for diabetic chronic kidney disease, stage 3. The patient has type 2 diabetes and takes insulin on a daily basis.
E11.22 Type 2 diabetes mellitus with diabetic chronic kidney disease
N18.3 Chronic kidney disease, stage 3 (moderate)
Z79.4 Long term (current) use of insulin
Rationale: There is a combination code for the type 2 diabetes with chronic kidney disease, and the tabular instructs the coder to use an additional code to identify the stage of the chronic kidney disease. At the E11 category level, the use additional code note instructs the coder to identify insulin use.
Diagnosis: A female patient with type 1 diabetes is seen for severe nonproliferative diabetic retinopathy with macular edema.
E10.341 Type 1 diabetes mellitus with severe nonproliferative diabetic retinopathy with macular edema
Rationale: There is a combination code for the type 2 diabetes with nonproliferative diabetic retinopathy with macular edema. No additional codes are necessary.
Diagnosis: A type 2 diabetic patient is evaluated for a chronic diabetic left foot ulcer with necrosis of muscle. The patient takes insulin on a daily basis.
E11.621 Type 2 diabetes mellitus with foot ulcer
L97.533 Non-pressure chronic ulcer of other part of left foot with necrosis of muscle
Z79.4 Long term (current) use of insulin
Rationale: The note under code E11.621 states to use additional code to identify site of ulcer (L97.4-L97.5-).
When reporting diabetes in pregnancy, many codes in chapter 15, “Pregnancy, childbirth and the puerperium (O00-O9A),” include a final character indicating the trimester of pregnancy. The trimester character assignment is valuable data to capture since poorly controlled diabetes in pregnancy during the second and third trimesters of pregnancy can result in excessively large babies, causing a medical risk to both the mother and newborn. Assignment of the final character for trimester is based on the provider’s clinical documentation of the trimester (or number of weeks) for the current admission or encounter. The time frames for the trimesters are indicated at the beginning of the chapter 15.
Coding for Diabetes Mellitus in Pregnancy
The trimester character assignment is valuable data to capture since poorly controlled diabetes in pregnancy during the second and third trimesters can cause a medical risk to both the mother and newborn.
A 32 year old female patient with type 1 diabetes is G2, P1, 26 weeks and is seen to evaluate her diabetes in pregnancy.
O24.012 Pre-existing diabetes mellitus, type 1, in pregnancy, second trimester
Z3A.26 26 weeks gestation of pregnancy
In chapter 19, “Injury, poisoning and certain other consequences of external causes (S00-T88),” category T85, Complications of other internal prosthetic devices, implants, and grafts, is used to report diabetic insulin pump complications. Category T85 requires the appropriate seventh character is added to each code to describe the encounter type (A: initial encounter, D: subsequent encounter, S: sequela).
Coding for Diabetes Mellitus with Insulin Pump
Category T85, Complications of other internal prosthetic devices, implants, and grafts, is used to report diabetic insulin pump complications.
A type 1 diabetic patient is seen in the ED to evaluate the leakage of her insulin pump. This is the patient’s initial encounter.
T85.633A Leakage of insulin pump, initial encounter
E08.69 Diabetes mellitus due to underlying condition with other specified complication
For more on coding diabetes mellitus in ICD-10-CM, see the “Coding Notes” in this month’s print issue.
Moczygemba, Jackie, and Susan H. Fenton. “Lessons Learned from an ICD-10-CM Clinical Documentation Pilot Study.” Perspectives in Health Information Management (winter 2012): 1-11. http://perspectives.ahima.org.
Centers for Medicare and Medicaid Services. “2012 ICD-10-CM and GEMs.” https://www.cms.gov.
Centers for Disease Control and Prevention. “2011 National Diabetes Fact Sheet.” www.cdc.gov/diabetes/pubs.
National Center for Health Statistics. “ICD-10-CM Official Guidelines for Coding and Reporting 2012.” Available under “Tools and Resources” at www.cdc.gov/nchs.
AHIMA. ICD-10-CM Coder Training Manual. Chicago, IL: AHIMA Press, 2012.