Glycated hemoglobin, (also referred to as glycohemoglobin, glycosylated hemoglobin, HbA1, GHb, or A1C), is a term used to describe a series of stable minor hemoglobin components formed from a combination of hemoglobin and glucose. It is used primarily to identify the plasma glucose concentration over time. This document addresses outpatient HbA_1c and glycated serum proteins (GSPs) testing, both of which have been used in the monitoring of glycemic control in the management of diabetes mellitus (DM).

For information regarding other methods to assess glycemic control for individuals with DM, see:

• CG-DME-42 Continuous Glucose Monitoring Devices
• CG-DME-50 Automated Insulin Delivery Systems
• CG-DME-51 External Insulin Pumps
• CG-LAB-30 Outpatient Laboratory-based Blood Glucose Testing

Clinical Indications

Medically Necessary:

Glycated serum protein testing (for example, hemoglobin (HbA_1c), albumin, or fructosamine) testing is considered medically necessary for any of the following indications (A-F):

1. The individual is between the ages of 35 and 71 and has overweight or obesity*; or
2. The individual is of any age and is from a population with disproportionately high prevalence of diabetes mellitus**; or
3. Hyperglycemia has been found on other testing; or
4. To test individuals who are pregnant and considered to be at high risk for type 2 diabetes mellitus; or
5. Prior testing at least 3 months previously showed results near diabetes mellitus diagnostic thresholds; or
6. To evaluate glycemic status for individuals with established diabetes mellitus, prediabetes, or a history of gestational diabetes when done no more often than the following test frequencies:
   1. Up to once yearly for individuals with prediabetes; or
   2. Up to two times per year for individuals with diabetes mellitus who are meeting treatment goals; or 
   3. As needed to assess individuals with diabetes mellitus when the following criteria are met (a or b):
      1. Not meeting treatment goals; or
      2. Therapy has recently changed;
         or
   4. Within the first year postpartum and then up to once yearly for individuals who have had gestational diabetes.

Notes:
See the Discussion section below for more information about:
*ADA, ACOG, and USPSTF recommendations about individuals who have overweight or obesity.
**See discussion section for information regarding populations at increased risk to develop diabetes mellitus.

Not Medically Necessary:

Glycated hemoglobin (HbA_1c) testing and glycated serum protein (for example, albumin or fructosamine) testing is considered not medically necessary when the criteria above are not met and for all other indications.