From the Guidelines
Hemolytic anemia typically causes a decrease in Hemoglobin A1c (HbA1c) levels rather than an increase. This occurs because hemolytic anemia is characterized by the premature destruction of red blood cells, which shortens their lifespan in circulation [ 1 ]. Since HbA1c is formed by the gradual glycation of hemoglobin over the 120-day lifespan of red blood cells, the accelerated turnover of these cells in hemolytic anemia means that hemoglobin has less time to become glycated. Consequently, patients with hemolytic conditions often have falsely low HbA1c values that may not accurately reflect their average blood glucose levels [ 1 ].
Key Considerations
- Hemolytic anemia shortens the lifespan of red blood cells, leading to decreased HbA1c levels [ 1 ]
- The degree of HbA1c reduction generally correlates with the severity of hemolysis [ 1 ]
- Alternative markers such as fructosamine or glycated albumin may be used to assess glycemic control in patients with hemolytic disorders [ 1 ]
Clinical Implications
- Clinicians should be aware of the potential for hemolytic anemia to affect HbA1c results [ 1 ]
- Patients with hemolytic conditions may require alternative methods for assessing glycemic control [ 1 ]
- The use of HbA1c as a diagnostic tool may be limited in patients with hemolytic anemia [ 1 ]
From the Research
Hemolytic Anemia and HbA1c Levels
- Hemolytic anemia can affect HbA1c levels, but the direction of the effect is not an increase, as might be expected in some cases of altered red blood cell dynamics.
- Studies have shown that hemolytic anemia tends to decrease HbA1c levels because the condition shortens the lifespan of red blood cells 2.
- This decrease occurs because HbA1c reflects the average blood glucose levels over the lifespan of red blood cells, which is typically around 3 months. If red blood cells are destroyed more quickly, as in hemolytic anemia, the HbA1c level may not accurately reflect the average blood glucose over the full 3-month period 3, 4, 5.
- In cases of hemolytic anemia, alternative measures such as fructosamine or glycated albumin may provide a more accurate assessment of blood glucose control, as these measures are less affected by red blood cell lifespan 3, 5.
- It's crucial to interpret HbA1c levels with caution in patients with hematologic diseases that alter red blood cell survival, as the HbA1c may not accurately reflect glycemic control in these cases 5.