Objective: Iron deficiency anemia (IDA) which is a global public health problem affecting both developing and developed countries, appears to be more common in diabetic patients compared to non-diabetic population. Gycosylated hemoglobin (HbA1c) which is widely considered as the primary target for glycemic control of diabetic patients, may be altered by certain condition including depletion of iron store with elevation of HbA1C concentrations independent of glycemia. However, reports of the clinical significance of iron deficiency on the glycosylated HbA1c levels have been inconsistent.

Case report: We report a case of 48-year-old diabetic patient with subclinical iron Deficiency, who was in a potential risk of receiving unneeded insulin injection because of false-high values of HbA1c.

Methodology: The false-high values of HbA1c (>7.0%) noticed earlier with the subclinical iron deficiency anemia (hemoglobin 12.7g/dL, serum iron: 7.94umol/L, ferritin: 7ng/mL), then after with frank iron deficiency anemia (hemoglobin 10.1g/dL, serum iron: 5.68u, mol/L, ferritin: 5.9ng/mL).

Results: Interestingly, this high value of HbA1c was subsequently fall (5.8%) simply on correcting the iron deficiency (Ferritin: 10.6ng/mL) by receiving iron supplementation.

Conclusion: We emphasizes that iron deficiency with or without anemia must be corrected before any diagnostic or therapeutic decision is made based on HbA1c in order to prevent misclassification of diabetes with its hazardous consequences of incorrect treatment.