ARTICOLO ORIGINALE   

La Rivista Italiana della Medicina di Laboratorio 2023 Marzo;19(1):41-50

DOI: 10.23736/S1825-859X.23.00179-2

Copyright © 2023 EDIZIONI MINERVA MEDICA

language: Italian

The preanalytical phase in the screening of gestational diabetes mellitus: a three-year evaluation from the implementations of the Diabetes Italian Study Group SIBioC/SIPMeL/SID

Graziella BONETTI ¹ ✉, Riccardo ADAMINI ², Antonio MARINO ¹, Graziella SAVERIAMPILLAI ¹, Gianfranco FIORDALISI ¹, Roberta VOLPI ¹, Nicolina AGOLA ³, Mariarosa CARTA ⁴

¹ SC Laboratorio Analisi, Dipartimento dei Servizi, ASST-Valcamonica, Esine, Brescia, Italia; ² Dipartimento di Ingegneria Meccanica e Industriale, Università degli Studi di Brescia, Brescia, Italia; ³ SC Servizio di Immunoematologia e Medicina Trasfusionale, Dipartimento dei Servizi, ASST-Valcamonica, Esine, Brescia, Italia; ⁴ Medicina di Laboratorio, AULSS 8 Berica, Vicenza, Italia

BACKGROUND: Gestational diabetes mellitus (GDM) represents the most common metabolic alteration found in pregnancy and affects the 6-7% of all pregnancies in Italy, with important maternal and fetal health outcomes. GDM screening, based on the risk factors, is carried out in Italy according to the ISS guidelines using OGTT 75 g at 24-28 weeks or 16-18 weeks of gestational age, applying the IADPSG criteria, derived from the HAPO study. Blood glucose over the cut-off even in a single point allows diagnosis of GDM. The aim of the present study is to evaluate the prevalence of GDM after application of the recommendations on the pre-analytical phase for blood glucose determination in the diabetes of the SIBioC/SIPMeL/SID Study Group on Diabetes.
METHODS: Data regarding OGTT for GDM screening before and after the application of the recommendations of the GdS Diabetes are extracted from the Laboratory Information System. OGTT for GDM screening was performed in 1188 women, median age 34 years (IQR: 30-37), on NaF/KOx sample (PRE group), was compared with OGTT in 1273 women, median age 34 years (IQR: 29-37) using a sample tube containing citrate/EDTA/NaF buffer acidified ternary mixture (POST group). Glycemia was determined by the hexokinase method on the Alinity c system in the POST group and by the glucose-oxidase method on the Vitros 3600 system in the PRE group.
RESULTS: GDM prevalence: 12.29% in PRE group, 31.34% in POST group (P<0.0001). Positivity only at T0 (basal glycemia): 6.31% in PRE group, 17.99% in POST group (P<0.0001), positivity only at 60’: 1.60% in PRE group, 2.67% in POST group (not statistically significant), positivity only at 120’: 1.35% in PRE group, 2.36% in POST group (not statistically significant). Positivity at all three points: 0.67% in the PRE group, 2.43% in the POST group (P=0.0005). Evaluating the distribution of glycemia at T0, 60’ and 120’, narrower curves are highlighted at T0 both in the PRE group (62÷119 mg/dL) and in the POST group (66÷119 mg/dL), compared to those at 60’ in the PRE group (49÷254 mg/dL) and in the POST group (52÷280 mg/dL) and those at 120’ in the PRE group (46÷218 mg/dL) and in the POST group (42÷233 mg/dL).
CONCLUSIONS: The recommendations of the GdS Diabetes on the pre-analytical phase for blood glucose determination in the diabetes applied since April 2019 have led to a significant increase in GDM. The very narrow distribution of frequencies in the basal glycemia could lead, even for minimal variations around the decision level of 92 mg/dL, to over or under diagnosis of GDM, even if the analytical goals of bias ≤2.1% according to the criteria of biological variability are achieved. From these real-life data, the importance of following the recommendations emerges since the non-application, such as the use of NaF alone in non-standardized conditions, could lead to the loss in the diagnosis of GDM with adverse events in the neonatal period and long-term complications in the mother and in the child.

KEY WORDS: Gestational diabetes; Pre-analytical phase; Sodium fluoride; Citric acid; Edetic acid