World Diabetes Day is November 14th

In observation of World Diabetes Day. -Click to read more about this event!


Diabetes is a number of diseases that involve problems with the hormone insulin. Normally, the pancreas (an organ behind the stomach) releases insulin to help your body store and use the sugar and fat from the food you eat.

Diabetes is a condition where there is too much sugar in the body for long periods of time. There are strong genetic factors related to some forms of diabetes, while other forms are attributed to weight gain and lack of exercise. The pancreas makes insulin, which helps the body use consumed sugars. Diabetes is caused by either the pancreas not producing enough insulin, or the cells of the body are unable to respond to the insulin produced. There are 4 main types of diabetes:

Type 1 = the body’s failure to produce enough insulin. This was previously known as “insulin-dependent” diabetes mellitus (IDDM), or “juvenile diabetes.”

Type 2 = this starts with “insulin resistance,” where the cells fail to use the insulin produced properly, but can progress to a lack of insulin over time. This was previously known as “non-insulin-dependent” diabetes mellitus (NIDDM), or “adult onset” diabetes.

Gestational Diabetes = when pregnant women without a previous history of diabetes develop high blood sugars during pregnancy requiring close monitoring. Many of these patients may convert back without diabetes after delivery, while others may continue to have diabetes.

Secondary Diabetes = when a patient without previous history of diabetes develops high blood sugars, usually as a result of: (a) an underlying condition, such as Cushing’s syndrome or pancreatitis, (b) a drug or chemical, such as steroidal use, or (c) a surgical procedure, such as a pancreatectomy.

Chronic diabetes conditions include type 1 diabetes and type 2 diabetes. Potentially reversible diabetes conditions include prediabetes — when your blood sugar levels are higher than normal, but not high enough to be classified as diabetes — and gestational diabetes, which occurs during pregnancy but may resolve after the baby is delivered.

A1C Test

The A1C test is a common blood test used to diagnose type 1 and type 2 diabetes and then to gauge how well you’re managing your diabetes. The A1C test goes by many other names, including glycated hemoglobin, glycosylated hemoglobin, hemoglobin A1C and HbA1c.

The A1C test result reflects the patient’s average blood sugar level for the past two to three months. Specifically, the A1C test measures what percentage of the patient’s hemoglobin — a protein in red blood cells that carries oxygen — is coated with sugar (glycated). The higher the A1C level, the poorer blood sugar control, exposing a higher risk of diabetes complications.

To Learn More about the Endocrine System, check out a video from our friends over at Crash Course by clicking here.

Did you know that the discovery of insulin won a Nobel Peace Prize? Read more about the discovery of insulin by clicking here.

Find the ADA Standards of Care for 2016 by clicking here.

Coding Diabetes

Diabetes codes in ICD-10-CM are greatly expanded, and are combination codes. In ICD-9-CM, it was appropriate to “code also” related manifestations of diabetes, but in ICD-10-CM, these are all reported in one code. All cause and effects of diabetes and any manifestations must be clearly documented by the provider, as coders may not assume any of these relationships between diagnoses.

In ICD-10-CM, Diabetes is coded by “Type” Type 1 (E10) vs. Type 2 (E11), with Type 2 being the default for Diabetes, NOS. 

Diabetes and the Use of Insulin:

If the documentation in a medical record does not indicate the type of diabetes but does indicate that the patient uses insulin, code E11, Type 2 diabetes mellitus, should be assigned. Code Z79.4, Long-term (current) use of insulin, should also be assigned to indicate the person uses insulin. Code Z79.4 should not be assigned if insulin is given temporarily to bring a Type 2 patient’s blood sugar under control during an encounter.

Z79.4/V58.67 Long term (current) use of insulin, are not necessary when reporting Type 1 diabetes.

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 principal or first-listed code, followed by code T38.3×6-, Underdosing of insulin and oral hypoglycemic (anti-diabetic) drugs. Additional codes for the type of diabetes mellitus and any associated complications due to the underdosing should also be assigned. (ICD-10-CM)

Overdose of insulin due to insulin pump failure:

The principle or first-listed code for an encounter due to an insulin pump malfunction resulting in an overdose of insulin, should be T85.6-, Mechanical complication of other specified internal and external prosthetic devices, implants and grafts, followed by code T38.3×1-, Poisoning by insulin and oral hypoglycemic (anti-diabetic) drugs, accidental (unintentional).

Coding Gestational Diabetes (Diabetes in Pregnancy)

Diabetes mellitus is a significant complicating factor in pregnancy. Pregnant women who are diabetic should be assigned a code from category O24, Diabetes mellitus in pregnancy, childbirth, and the puerperium, first, followed by the appropriate diabetes code(s) (E08-E13) from chapter 4.

Gestational (pregnancy induced) diabetes can occur during the second and third trimester of pregnancy in women who were not diabetic prior to pregnancy. Gestational diabetes can cause complications in the pregnancy similar to those of pre-existing diabetes mellitus. It also puts the woman at greater risk of developing diabetes after the pregnancy. Codes for gestational diabetes are in subcategory O24.4, Gestational diabetes mellitus. No other code from category O24, Diabetes mellitus in pregnancy, childbirth, and the puerperium, should be used with a code from O24.4.

The codes under subcategory O24.4 include diet controlled and insulin controlled. If a patient with gestational diabetes is treated with both diet and insulin, only the code for insulin-controlled is required.

Code Z79.4, Long-term use of insulin, should not be assigned with codes from subcategory O24.4.

An abnormal glucose tolerance in pregnancy is assigned a code from subcategory O99.81, Abnormal glucose complicating pregnancy, childbirth, and the puerperium.

Coding Secondary Diabetes

There are 3 separate categories for selection of secondary diabetes codes.

E08 = Diabetes mellitus due to underlying condition

Code first the underlying condition, such as:

Congenital rubella (P35.0)

Cushing’s syndrome (E24.-)

Cystic fibrosis (E84.-)

Malignant neoplasm (C00-C96)

Malnutrition (E40-E46)

Pancreatitis and other diseases of the pancreas (K85.-, K86.-)

Use additional code to identify any insulin use (Z79.4)

E09 = Drug or chemical induced diabetes mellitus

Code first poisoning due to drug or toxin, if applicable (T36-T65 with fifth or sixth character 1-4 or 6)

Use additional code for adverse effects, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)

Use additional code to identify any insulin use (Z79.4)

E13 = Other specified diabetes mellitus

Diabetes mellitus due to genetic defects of beta-cell function

Diabetes mellitus due to genetic defects in insulin action

Postpancreatectomy diabetes mellitus

Postprocedural diabetes mellitus

Secondary diabetes mellitus NEC

Use additional code to identify any insulin use (Z79.4)



Brian Boyce, BSHS, CPC, CPC-I, CRC, CTPRP is an AAPC-approved PMCC medical coding instructor, and ICD-10-CM trainer and the author of the AAPC CRC® curriculum. He has specialized in risk adjustment from the very beginnings of these models being utilized and has assisted large and small clients nationally. He has special interest in ethics, patient safety, disease management, and management and leadership of people. Brian is a veteran of Desert Storm, where he served on active duty with the US Air Force with a job specialty of Aeromedical Evacuation. He went into physician practice management and medical coding after an honorable discharge. He is the CEO of ionHealthcare®, LLC, a company that specializes in risk adjustment coding & support services. For additional inquiries contact ionHealthcare® at