Haemoglobin A1C Levels Constantly Below Lower Reference Limit in a Diabetic Patient With Microcytic Anaemia

Authors

• Frank Sheng Fan Section of Haematology and Oncology, Ministry of Health and Welfare Taitung Hospital, Taitung County, Taiwan
• Chih-Hao Chen Section of Cardiology, Department of Medicine, Ministry of Health and Welfare Taitung Hospital, Taitung County, Taiwan
• Hui-Chun Yang Department of Laboratory Medicine, Ministry of Health and Welfare Taitung Hospital, Taitung County, Taiwan

fantast.fan@msa.hinet.net

Keywords

Abstract

Introduction: Haemoglobin A_1C (A1C), as a parameter of long-term glycaemic control, has been adopted to guide diabetic therapy all over the world. However, falsely high or low A_1C could be troublesome in daily practice.
Case description: A 75-year-old male diabetic patient affected by a reasonably inferred life-long history of microcytic anaemia was found to have abnormally low A_1C values in the previous 5 months. Subsequent laboratory assessment with brilliant cresyl blue staining and haemoglobin electrophoresis detected haemoglobin H disease as the underlying cause of both the microcytic anaemia and the disturbed A_1C measurement.
Discussion: Enhanced erythrocyte destruction such as in haemoglobin H disease could explain a falsely decreased A_1C level very well. Upon facing a questionable A_1C value, physicians dealing with diabetes should consider the possibility of undiscovered underlying causes rather than too tightly glycaemic control.