A-053 Low HbA1c: When Numbers Lie – Uncovering Hidden Conditions and Lab Pitfalls

Abstract Background Hemoglobin A1c (HbA1c) is the gold standard for gauging long-term glycemic control and diagnosing diabetes, offering a snapshot of average blood glucose levels over the past 8–12 weeks. Despite its utility, HbA1c levels were consistently low in a few of our patients, raising concerns among providers about the potential for artifactually lowered values in certain clinical scenarios at our hospital, leading to diagnostic inaccuracies. This phenomenon raises significant concerns among healthcare providers regarding the underlying etiologies of these aberrant values and the subsequent clinical management of affected individuals. This study aims to investigate instances of anomalously low HbA1c values (<4%) to elucidate potential medical conditions contributing to these findings and to evaluate the limitations of the HbA1c measurement techniques employed in our hospital*s clinical laboratory. Methods This three-year retrospective study (2021–2023) analyzed HbA1c values below 4% using clinical laboratory data. Patient variables, including medical record number (MRN), age, sex, race, diabetes status, and relevant comorbidities, were systematically reviewed. To maintain analytical rigor, cases with incomplete data or insufficient follow-up were excluded. HbA1c concentrations were quantified using an immunoassay based on the principle of turbidimetric immunoinhibition. Results This study analyzed three years of HbA1c data (2021–2023) from 245,923 tests, identifying 100 cases (0.041%) with HbA1c levels below 4%. Low HbA1c values were more prevalent among African American (59%) and female (58%) individuals. Among affected patients, 26% had diabetes, 66% had anemia—primarily iron deficiency anemia, anemia of chronic disease, or sickle cell anemia—33% required blood transfusions, 19% had chronic kidney disease (CKD) or end-stage renal disease (ESRD), 23% had liver disease, and 18% had hemoglobinopathies. These findings highlight the complex interplay between HbA1c levels and chronic conditions, suggesting that factors such as anemia and renal dysfunction may contribute to artificially low values. Given these associations, reliance on HbA1c alone for glycemic assessment in patients with multiple comorbidities may lead to diagnostic inaccuracies, underscoring the need for alternative testing methods and a more comprehensive approach to patient management. Conclusion This study highlights the prevalence of low HbA1c levels among African American and female individuals, particularly those with anemia and chronic conditions. The impact of anemia on HbA1c measurements suggests a potential for diagnostic inaccuracy, reinforcing the need for alternative glycemic assessment methods. Furthermore, the association between low HbA1c, transfusion dependence, and comorbidities such as kidney disease, liver disease, and diabetes underscores the necessity of a comprehensive, multidisciplinary approach to patient care. These findings emphasize the importance of individualized management strategies and broader diagnostic tools to ensure accurate disease monitoring and effective treatment, particularly in patients with multiple comorbidities.