How often should Hemoglobin A1C (HbA1C) levels be checked for individuals with diabetes (DM) and prediabetes?

Frequency of A1C Testing for Diabetics and Prediabetics

A1C should be tested at least twice yearly for patients with diabetes who are meeting treatment goals and have stable glycemic control, and quarterly (every 3 months) for those whose therapy has changed or who are not meeting glycemic goals. 1, 2

Testing Recommendations Based on Glycemic Control

For Patients with Stable Glycemic Control:

• Test A1C at least twice per year (every 6 months) for patients who are meeting treatment goals and have stable glycemic control 1, 2
• This recommendation applies to both type 1 and type 2 diabetes patients with good control 1

For Patients with Unstable Glycemic Control:

• Test A1C quarterly (every 3 months) for patients whose therapy has recently changed 1
• Test A1C quarterly for patients who are not meeting glycemic goals 1
• More frequent testing may be needed for patients with severe hypoglycemia or hyperglycemia 1
• More intensive monitoring is recommended during periods of rapid growth and development in youth 1

For Prediabetic Patients:

• While specific testing frequency for prediabetics is not explicitly stated in the guidelines, monitoring at least twice yearly would be reasonable based on the recommendations for stable diabetic patients 2
• Testing should be guided by clinical judgment and individual risk factors 1

Benefits of Appropriate Testing Frequency

• Regular A1C testing helps determine whether glycemic targets have been reached and maintained 1
• Point-of-care A1C testing provides opportunities for more timely treatment decisions and therapy changes 1, 2
• Adherence to recommended testing frequency is associated with better glycemic control 3
• A1C reflects average glycemia over approximately 2-3 months and has strong predictive value for diabetes complications 1

Limitations and Special Considerations

• A1C does not provide information about glycemic variability or hypoglycemia 1, 2
• For patients prone to glycemic variability (especially type 1 diabetes), glycemic control is best judged by combining A1C results with self-monitoring of blood glucose or continuous glucose monitoring 1
• Conditions affecting red blood cell turnover (hemolysis, blood loss, anemias) can interfere with A1C accuracy 1, 2, 4
• Hemoglobin variants can affect some A1C assays, though most modern assays can handle common variants 1

Common Pitfalls to Avoid

• Insufficient testing frequency for patients with unstable control can delay necessary treatment adjustments 2, 5
• Excessive testing beyond recommendations provides little additional clinical value and wastes resources 2
• Failure to consider factors that may affect A1C results can lead to inappropriate treatment decisions 2, 4
• Relying solely on A1C without considering blood glucose monitoring data, especially in patients with glycemic variability 1

Alternative Monitoring Methods

• When A1C cannot be reliably measured (due to hemoglobin variants or conditions affecting red blood cell turnover), consider alternative methods such as fructosamine, glycated albumin, or continuous glucose monitoring 1, 4
• For patients with sickle cell disease or other homozygous hemoglobin variants, A1C cannot be measured and alternative monitoring methods must be used 1