what can cause false reading in hemoglobin a1c?

Medical Misconception: It’s all about the A1C! (For Assessing Diabetes Control)

Hemoglobin A1C (or just A1C for short) is a blood test that measures the amount of sugar that is attached to the hemoglobin protein in red blood cells.

For years it has been the diabetes measure that medical providers have paid attention to most to determine how well diabetes control is going.

It’s undoubtedly helpful - but it is also important to know what can cause false readings in hemoglobin A1C:

Iron deficiency (falsely higher readings)

Recent blood transfusion (falsely lower readings)

Hemodialysis (falsely lower readings)

Plus - A1C levels are drawn every 3 months.

Q: Why?

A: The average lifetime of a red blood cell is ~90 days and therefore it takes 3 months to use the A1C as a feedback tool on whether a new lifestyle approach or medicine regimen is effective.

Enter daily blood sugar checks.

Whether you check with a fingerstick or use a continuous glucose monitor (aka CGM),

knowing your blood sugars throughout the day on a day to day basis provides real time feedback about your habits and how well medicines are working!

Data also suggests the variability of blood sugars is important - how much they swing. Stay tuned for more news on this…data suggests the less swings, the better for preventing complications.

So while there is still a role for A1C - I stress the daily trends much more if we can get them and am interested in these readings because they are real-time (don’t have to wait 3 months)!