Can HbA1c be too low?

While it is possible for your HbA1c to be too low, it is very rare. HbA1c under 4.0% is considered extremely low and is associated with a significant increase in all-cause mortality. Although it is not well understood why a low HbA1c is associated with an increase in all-cause mortality, it is likely because individuals with other conditions such as iron-deficiency anemia, liver diseases/disorders, or inflammatory conditions have lower circulating glucose or lower hemoglobin levels that can affect their HbA1c. If your HbA1c is extremely low, you need to speak with a health care provider to discuss your results.