Background: Megaloblastic anemia is a subtype of anemia with increased red blood cell volume. These megaloblastic cells can be easily destroyed in the bone marrow and spleen, leading to ineffective hematopoiesis. Insulin-degrading enzymes (IDE) in erythrocytes can break down the insulin into amino acid fragments; thus, when hemolysis occurs, IDE can be released into the blood, resulting in low insulin measurement values.
Methods: This article reports a case of false insulin test results due to the hemolysis resulting from megaloblastic anemia.
Results: The patient's first fasting glucose results indicated that the glucose and C-peptide levels were within the normal range while her insulin level was abnormally low. After hemolysis was corrected, the relevant indicators were re-evaluated and all the results were normal.
Conclusions: This article reports a patient diagnosed with megaloblastic anemia, whose dysmorphic erythrocytes cause severe extravascular hemolysis. It was the occurrence of hemolysis that the IDE released into the blood, leading to the abnormal insulin test result.