# Unexpectedly Low HbA1c in a Patient With Newly Diagnosed Diabetes Mellitus and Thalassemia Trait: A Case Report

## TL;DR

A patient with diabetes and thalassemia trait had a misleadingly low HbA1c due to the blood disorder, showing the need for alternative glucose monitoring methods.

## Contribution

Highlights the diagnostic challenge of using HbA1c in patients with thalassemia trait and advocates for alternative glycemic monitoring strategies.

## Key findings

- A patient with diabetic ketosis had unexpectedly low HbA1c due to thalassemia trait.
- Thalassemia trait affects red blood cell turnover and interferes with HbA1c assays.
- Alternative methods like continuous glucose monitoring are needed for accurate diabetes management in such cases.

## Abstract

Hemoglobin A1c (HbA1c) is widely used to assess long-term glycemic control in patients with diabetes mellitus; however, its reliability may be compromised in certain clinical scenarios, including hemoglobinopathies. We report the case of a 46-year-old man who presented with symptoms of hyperglycemia and was found to have diabetic ketosis. Despite significant hyperglycemia, his HbA1c was markedly low. Further evaluation confirmed the presence of thalassemia trait, which explained the discrepancy due to its impact on red blood cell turnover and HbA1c assay interference. This case highlights the importance of recognizing conditions that can distort HbA1c values and the need to use alternative glycemic monitoring strategies such as continuous glucose monitoring, corrected HbA1c, and serum fructosamine in such patients. Accurate interpretation of glycemic markers in the context of hemoglobinopathies is essential for appropriate diagnosis and effective diabetes management.