English 
Italian CONTRIBUTI SCIENTIFICI – Scientific Papers
Volume:
Biochimica Clinica 2020; 44(2) 143-148
Pubblicato on-line:
January 1, 2020
DOI:
10.19186/BC_2020.006
Il tipo di campione per la curva da carico orale di glucosio è fondamentale per una corretta identificazione del diabete mellito gestazionale
An appropriate sample for oral glucose tolerance test is fundamental for a correct identification of gestational diabetes mellitus
AUTORI
1Laboratorio di Patologia Clinica, A.S.S.T. - Valcamonica
2Medicina di Laboratorio, Ospedale San Bortolo, AULSS 8 Berica, Vicenza
3Laboratorio Centrale Analisi Chimico Cliniche, A.S.S.T.- Spedali Civili, Brescia
*Gruppo di Studio SIBioC-SIPMeL Diabete mellito
ABSTRACT
An appropriate sample for oral glucose tolerance test is fundamental for a correct identification of gestational diabetes mellitus.
Background: Gestational Diabetes Mellitus (GDM) is diagnosed by the oral glucose tolerance test (OGTT) using Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study-derived definite cut-off values, where reference glucose is determined in sodium fluoride (NaF) containing tubes immediately centrifuged. The aim of the present study is to evaluate the effect of the use of the recommended citrate containing tubes, as immediate glycolisis inhibitor, for OGTT as screening for GDM, comparing them with NaF containing tubes, used in routine laboratory conditions.
Methods: a total of 83 pregnant women were enrolled in the study; OGTT (75 g) was carried out in the Clinical Laboratories of Brescia and Vicenza in all the subjects for screening of GDM. All subjects signed written informed consent to participate in the study. Glucose determination was performed using three different types of glycolysis inhibitor: [sodium fluoride (NaF, in both laboratories), a lyophilized acidified mixture (FC-MIX, in Vicenza), and a liquid acidified mixture (GlucoEXACT, in Brescia)]. The glucose concentration was measured by an hexochinase method on Dimension Vista systems from Siemens Healtheers. The International Association of Diabetes and Pregnancy Study Groups (IAPDGS) criteria, derived from the HAPO study, were used for the diagnosis of GDM.
Results: Using NaF and FC-mix tubes, 6/51 (11.8%) and 12/51 (23.5%) women respectively, were diagnosed having GDM in Vicenza. Using NaF and GlucoEXACT tubes 2/31 (6.5%) and 6/31 (18.8%) women respectively, were diagnosed having GDM in Brescia. There was a statistically significant difference (p<0.05) between NaF and citrate acidified mixture in the glucose measurements at all time points.
Conclusions: The use of the tubes containing a mixture of NaF, EDTA and citrate is a useful and necessary pre-analytical tool for an accurate OGTT, when utilized for the screening of GDM. Tubes containing NaF alone should no longer be used for screening of GDM because their use results in underdiagnosis of GDM.