A Nondiabetic Case of Hemoglobin Variant (Hb Niigata) with Inappropriately High and Low HbA1c Titers Detected by Different Methods

Open Access
Publisher Website
Google Scholar
Abstract
Human adult hemoglobin (Hb) consists of HbA (96% of the total), HbA2 (3%), and HbF (1%). HbA contains a number of subfractions, including HbA1a2, HbA1b, and HbA1c (glycosylated Hb). HbA1c has been used as a clinical marker for blood sugar control for the past one to two months. Inappropriately low or high HbA1c concentrations in comparison with blood glucose concentrations are caused by various conditions of Hb structure and metabolism; under such conditions, the use of HbA1c as a clinical marker cannot be warranted. Abnormally low HbA1c concentrations are usually encountered in patients with high turnover rates of Hb, whereas disproportionately high HbA1c concentrations are found under relatively rare conditions. Various hereditary Hb variants have been reported to cause disproportionately high and low HbA1c titers, as determined by chromatographic methods such as HPLC (1)(2)(3)(4)(5)(6).