National survey on the execution of the oral glucose tolerance test (OGTT) in a representative cohort of Italian laboratories
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Marco Orsini Federici
Abstract
Background: Recently revised diagnostic criteria for diabetes mellitus and the lack of universal agreement on the methodology for the screening and diagnosis of gestational 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 75g of glucose in adults and 1.75g/kg for children as recommended by WHO was performed by 87.1% of the laboratories. WHO indications to collect samples at baseline and at 120min 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.
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©2006 by Walter de Gruyter Berlin New York
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Articles in the same Issue
- CCLM: Expanding the science worldwide
- Factor V Leiden, prothrombin G20210A substitution and hormone therapy: indications for molecular screening
- Immunochemical quantification of free immunoglobulin light chains from an analytical perspective
- De novo deletion removes a conserved motif in the C-terminus of ABCA4 and results in cone-rod dystrophy
- Molecular detection of squamous cell carcinoma antigen transcripts in peripheral blood of cancer patients
- Influence of human haptoglobin polymorphism on oxidative stress induced by free hemoglobin on red blood cells
- Real-time RT-PCR quantification of PRAME gene expression for monitoring minimal residual disease in acute myeloblastic leukaemia
- Association of high-sensitive C-reactive protein with advanced stage β-cell dysfunction and insulin resistance in patients with type 2 diabetes mellitus
- A longitudinal evaluation of urinary glycosaminoglycan excretion in normoalbuminuric type 1 diabetic patients
- National survey on the execution of the oral glucose tolerance test (OGTT) in a representative cohort of Italian laboratories
- The reduction of cholesteryl linoleate in lipoproteins: an index of clinical severity in β-thalassemia/Hb E
- Alterations in serum glycosaminoglycan profiles in Graves' patients
- Alterations in anti-oxidative defence enzymes in erythrocytes from sporadic amyotrophic lateral sclerosis (SALS) and familial ALS patients
- Sandwich ELISAs for soluble immunoglobulin superfamily receptor translocation-associated 2 (IRTA2)/FcRH5 (CD307) proteins in human sera
- Utilizing ultrafiltration to remove alkaline phosphatase from clinical analyzer water
- Measurement of serum monoclonal components: comparison between densitometry and capillary zone electrophoresis
- Salivary aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase: possible markers in periodontal diseases?
- Reticulocyte count, mean reticulocyte volume, immature reticulocyte fraction, and mean sphered cell volume in elite athletes: reference values and comparison with the general population
- Serum homocysteine levels and paraoxonase 1 activity in preschool aged children in Greece
- The effects of adrenocorticotrophic hormone and cortisol on homocysteine and vitamin B concentrations
- Plasma, salivary and urinary cotinine in non-smoker Italian women exposed and unexposed to environmental tobacco smoking (SEASD study)
- Cut-off values for total serum immunoglobulin E between non-atopic and atopic children in north-west Croatia
- Thyroglobulin assay during thyroxine treatment in low-risk differentiated thyroid cancer management: comparison with recombinant human thyrotropin-stimulated assay and imaging procedures
- Evaluation of serum levels of p53 in hepatocellular carcinoma in Egypt
- Insufficient filling of vacuum tubes as a cause of microhemolysis and elevated serum lactate dehydrogenase levels. Use of a data-mining technique in evaluation of questionable laboratory test results
- Evaluation of three different specimen types (serum, plasma lithium heparin and serum gel separator) for analysis of certain analytes: clinical significance of differences in results and efficiency in use
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