Comparison of Citrate-Fluoride-EDTA with Fluoride-EDTA Additives to Stabilize Plasma Glucose Measurements in Women Being Screened during Pregnancy with an Oral Glucose Tolerance Test: A Prospective Observational Study.

To the Editor:We recently highlighted the importance of implementing recommended preanalytical standards to avoid missing the diagnosis of gestational diabetes mellitus (GDM)1(1). The placement of samples on an ice slurry with separation within 30 min, however, is not always practical. We therefore carried out a prospective observational study to compare the incidence of GDM and mean glucose concentrations after stabilizing maternal glucose samples with a citrate-fluoride-EDTA (CFE) tube with the incidence after stabilization with fluoride-EDTA (FE) tubes. Both index tests were benchmarked against the ideal reference (2).Selectively screened women were recruited with consent when they presented for a routine 24–32 weeks oral glucose tolerance test (OGTT). Exclusion criteria were multiple pregnancy, age u003c18 years, and inability to understand English.The primary outcome was any increased glucose concentration diagnostic for GDM at the time of a 75-g OGTT using the International Association of Diabetes and Pregnancy Study Groups (IADPG) criteria (3). We included 121 women with tripled samples to determine the effect of sample handling on the incidence of GDM. ANOVA and McNemaru0027s test were used to determine statistical significance.We obtained 3 venous samples at …