How often should I check my Hemoglobin A1c (HbA1c) levels?

Hemoglobin A1c Testing Frequency

Check your hemoglobin A1c every 3 months until you reach your target goal, then reduce testing to every 6 months once your diabetes is well-controlled and stable. 1

Standard Testing Schedule

For Patients Not Meeting Goals or With Recent Treatment Changes

• Test every 3 months (quarterly) if:
  • Your therapy has recently changed 1
  • You are not meeting your glycemic targets 1
  • You recently started new medications like insulin or metformin 2
  • Your diabetes control is unstable 1

The 3-month interval is optimal because HbA1c reflects your average blood glucose over approximately the previous 2-3 months, making this the appropriate timeframe to assess whether treatment adjustments are working 1

For Patients Meeting Goals With Stable Control

• Test at least every 6 months (twice yearly) once you have:
  • Achieved your HbA1c target 1
  • Maintained stable glycemic control 1
  • No recent changes to your treatment regimen 1

Some patients with exceptionally stable control well within target may do well with testing only twice per year 1

Special Circumstances Requiring More Frequent Testing

• More frequent than quarterly testing may be appropriate for:
  • Pregnant women with type 1 diabetes 1
  • Highly intensively managed patients 1
  • Patients with very unstable glycemic control 1

Critical Timing Considerations

Avoid Testing Too Early

• Do not check HbA1c before 2-3 months after starting or changing treatment, as it will not reflect the full treatment effect and could lead to premature medication adjustments 2

Do Not Delay Scheduled Testing

• Recheck at exactly 3 months when therapy has changed - do not postpone this assessment as treatment intensification recommendations should not be delayed 2

What HbA1c Testing Shows You

• HbA1c reflects your average blood glucose levels over the past 2-3 months, with results weighted more heavily toward the most recent month 1, 3
• It has strong predictive value for diabetes complications 1
• It can confirm the accuracy of your home glucose meter readings 1

Important Limitations to Understand

HbA1c Does Not Measure:

• Day-to-day glucose variability 1
• Episodes of hypoglycemia (low blood sugar) 1
• Real-time glucose levels 1

Conditions That Affect Accuracy:

• Hemolytic anemia (falsely lowers HbA1c) 3
• Blood loss (falsely lowers HbA1c) 1, 2
• Aplastic anemia (falsely raises HbA1c) 3
• Hemoglobin variants 1, 2
• Recent blood transfusions 2

If your HbA1c result doesn't match your home glucose readings, discuss these potential interfering factors with your healthcare provider 1, 2

Between HbA1c Tests

• Continue regular home blood glucose monitoring as prescribed by your healthcare provider 1
• The frequency of home monitoring depends on your specific insulin regimen and diabetes type 1, 2
• Patients on intensive insulin therapy may need to check blood glucose 6-10 or more times daily 1