Can dehydration affect the accuracy of an HbA1c test?

Dehydration doesn’t directly affect HbA1c results, but it can make blood draws more difficult by constricting veins. The HbA1c test measures glycated haemoglobin, which reflects blood sugar levels over the past 2-3 months, so it’s not impacted by short-term hydration status. However, staying hydrated before a blood draw can make the procedure more comfortable and improve the accuracy of the sample collection. If you have concerns about dehydration or other factors affecting your health, discuss them with your healthcare provider before the test.