National survey on the execution of the oral glucose tolerance test (OGTT) in a representative cohort of Italian laboratories
Articolo
Data di Pubblicazione:
2006
Citazione:
National survey on the execution of the oral glucose tolerance test (OGTT) in a representative cohort of Italian laboratories / M. Orsini Federici, A. Mosca, R. Testa, A. Lapolla, P. Andreani, M. Massi Benedetti. - In: CLINICAL CHEMISTRY AND LABORATORY MEDICINE. - ISSN 1434-6621. - 44:5(2006), pp. 568-573. [10.1515/CCLM.2006.100]
Abstract:
Background: Recently revised diagnostic criteria for diabetes mellitus and the lack of universal agreement on the methodology for the screening and diagnosis of stational diabetes mellitus (GDM) still generate inconsistency in execution of the oral glucose tolerance test (OGTT). The aim of the present survey was to evaluate the adherence of Italian laboratories to the
internationally accepted guidelines in carrying out the OGTT for the diagnosis of diabetes in the general population and for the screening of GDM.
Methods: A questionnaire was designed to investigate the following issues related to the OGTT: 1) the relationship between laboratories and diabetes centres for the definition of standard protocols; 2) the
amount of glucose administered; 3) the number and timing of blood samples; 4) the procedures used for the screening and diagnosis of GDM; and 5) reference
to WHO guidelines for the interpretation of the results. The questionnaire was administered to 400 specialists in laboratory medicine working in public or
private laboratories nationwide participating in the ‘‘Italian External Evaluation of Quality in Laboratory
Medicine’’ Study Group.
Results: The survey was completed in the period from June to September 2003. In the observation period,241 questionnaires were returned by specialists working in laboratories scattered throughout 15 out
of the 20 Italian regions. Only 50% of the laboratories performed the OGTT according to protocols defined in agreement with local reference diabetes centres.
OGTT using 75 g of glucose in adults and 1.75 g/kg for children as recommended by WHO was performed by 87.1% of the laboratories. WHO indications to collect
samples at baseline and at 120 min were followed by 33.2% of the centres. Higher variability was highlighted with respect to the methodology for GDM screening: 49.8% of the laboratories always adopted the two-step procedure consisting of a glucose challenge test (GCT) and subsequent OGTT in positive cases; 4.9% performed the 100-g OGTT with four blood samples; 1.6% the 75-g OGTT with two blood samples; and 2.7% the 75-g OGTT with four blood samples. More than 30% of the centres referred to
different diagnostic schemes, 62% of which used individually chosen procedures amongst those reported above, 19% used only the GCT and no subsequent OGTT in positive cases, and 18.4% used a variety of completely different, arbitrarily chosen methods.
Finally, only 25.6% of the laboratories referred to the WHO limits for interpretation of the results.
Conclusions: For the Italian laboratories investigated, relevant variability was highlighted for performance of the OGTT in general and GDM screening in particular.
A variable relationship between laboratories and diabetes centres was also detected, which might represent
a relevant indicator for the need for rationalisation or standardisation of the method for performing an OGTT. These data highlight the need for greater collaboration between these different bodies. We suggest that other similar investigations should be carried out in other countries within the framework of the IFCC Global Campaign on Diabetes Mellitus.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Diabetes diagnosis; GDM screening; Gestational diabetes mellitus (GDM); Oral glucose tolerance test
Elenco autori:
M. Orsini Federici, A. Mosca, R. Testa, A. Lapolla, P. Andreani, M. Massi Benedetti
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