The Effects of Storage and Additives on Postmortem HbA1c Measurements

Abstract

HbA1c is used in forensic toxicology to identify undiagnosed diabetes mellitus (DM) and those with poor glycemic control prior to death. HbA1c is typically measured in whole blood collected in tubes containing ethylenediaminetetraacetic acid (EDTA). The effect of other additives, including sodium fluoride (NaF), is unclear. Furthermore, the assessment of short- and long-term stability of HbA1c has produced conflicting results. In this study, we collected paired postmortem blood samples in EDTA and NaF tubes (n = 142) to assess their comparability for HbA1c measurement. Stability was assessed by measuring HbA1c at baseline, 2, 3, and 4 weeks postcollection (stored at 4°C) and at 2, 4, 6, and 12 months postcollection (stored at -20°C). We found no significant difference in HbA1c between the two preservatives at any of the time points indicating NaF is a suitable preservative for HbA1c measurement. We also determined that DM status, postmortem interval, and decomposition had no effect on stability.

Evaluation and Validation of Utility of BD Glucose Vacutainer for Glycosylated Hemoglobin Assay for Timely Therapeutic Management of Diabetes Mellitus

“…A small pilot study on three diabetic and three non-diabetic samples evaluated the stability of HbA1c in EDTA, heparin, citrate and fluoride and found no significant changes when sample was stored at -4C for seven days [7]. Another study found no significant difference in HbA1c or its stability between parallel post-mortem samples collected in EDTA and sodium fluoride vacutainers and stored at 4C [8].…”