THU253 The Hemoglobin Wayne Variant And Association With Falsely Elevated HbA1c

Abstract

Abstract Disclosure: N. Mulpuri: None. A. Bryant: None. D. Shahin: None. K. Soe: None. Background: Hemoglobin Wayne (Hb Wayne) is a rare, silent alpha chain variant caused by a frameshift mutation in the HbA2 gene. Although clinically silent, this mutation falsely elevates HbA1c values. Clinical cases: We are presenting three cases of Hb Wayne patients referred to our diabetes clinic within the last 5 years. All three cases were Caucasian-American males diagnosed with uncontrolled diabetes based on high HbA1c values of ranging from 10.1-10.6 %. One of the patients was initially started on metformin while the other patients’ treatment plan included dietary and lifestyle modifications. Review of the labs showed that renal function, complete blood count and fasting plasma glucose were within the normal range. High HbA1c value was noted by routine screening lab without having any symptoms related to DM or features of insulin resistance. The discrepancy between high HbA1c values and other glycemic index parameters (serum glucose and FSBG values) was noted. Subsequently, further work up was done (repeat HbA1c with different assay and fructosamine) to verify the diagnosis of uncontrolled DM. Fructosamine levels and repeat HbA1c with a different assay (enzymatic assay at Quest lab) were normal. Hemoglobin electrophoresis confirmed presence of an abnormal alpha variant consistent with Hb Wayne. The patients were reassured and educated about this Hb variant, and no further treatment for DM was pursued. Conclusion: Rare hemolgobinopathies may be more common than previously expected as they can be clinically silent and easily overlooked. While HbA1c has been an important clinical tool for diagnosis and management of diabetes, clinicians should look for underlying reasons which can affect HbA1c assay if there is any discrepancy between HbA1c, FSBG and plasma glucose values. The laboratory at our institution uses cation- exchange High Performance Liquid Chromatography method (Bio-Rad D-100 instrument) resulting in falsely high HbA1c values. Some hemoglobinopathies can affect the widely used HbA1c testing method such as CE-HPLC. The impact on HbA1c values will differ depending on hemoglobin variant and specific method and assay used. Given the limitations of HbA1c testing, clinicians should avoid relying heavily on HbA1c values in management and diagnosis of diabetes. It is vital that clinicians use their clinical judgment to correlate HbA1c with other clinical parameters such as continuous glucose monitoring data, glycated albumin,1,5 anhydroglucitrol (1,5 –AG), fingerstick blood glucose, plasma glucose and fructosamine values. Presentation: Thursday, June 15, 2023