Which systemic condition can cause a falsely low hemoglobin A1c measurement?

Falsely low hemoglobin A1c measurements can occur during pregnancy due to several physiological changes that affect hemoglobin and glucose metabolism. During pregnancy, there is an increase in red blood cell turnover as the body prepares to supply enough oxygen to both the mother and the developing fetus. With this increased turnover, the lifespan of red blood cells is shortened, which means that the average glucose exposure to hemoglobin is lower than it would be in a non-pregnant state. As a result, the HbA1c levels may not accurately reflect the mother's glycemic control.

In contrast, chronic opioid use and alcoholism do not typically interfere with the measurement of hemoglobin A1c in a direct manner that would significantly lead to falsely low readings. Hyperbilirubinemia can affect some laboratory tests, but its direct impact on A1c measurement is not as pronounced as the physiological changes seen during pregnancy. Thus, pregnancy is the systemic condition most likely to cause this discrepancy in hemoglobin A1c results.