Background. HbA1c has a key role for diagnosing diabetes and monitoring glycemic state. Knowledge of its biological variation (BV) is critical for result interpretation. As recently published results showed a marked heterogeneity of available BV data, we revaluated HbA1c BV using a well designed protocol. Methods. We took five blood specimens from 18 apparently healthy subjects (9 men and 9 women, ages 26-52 years) on the same day every two weeks for two months. Samples were stored at -80°C until analysis and assayed in duplicate in a single run by Roche Tina-quant Gen.2 immunoassay on the Integra 400 platform. Data were analyzed by the ANOVA. To assess the assay traceability to the IFCC reference method, we preliminarily carried out a correlation experiment on four blood samples. Results. The regression equation (Tina-quant = 1.05 IFCC reference method – 1.6 mmol/mol) confirmed the alignment of the employed assay. There were no differences in HbA1c values between men and women (global mean, 36 mmol/mol). Within- (CVI) and between-(CVG) subject BV were 2.5% and 7.1%, respectively. Desirable analytical goals derived from BV for imprecision (0.50 CVI), bias [0.25 (CVI 2 + CVG 2)1/2] and total error [1.65 (0.5 CVI) + 0.25 (CVI 2 + CVG 2)1/2] were 1.25%, 1.88%, and 3.94%, respectively. HbA1c had marked individuality, therefore the use of population-based reference limits could be inadequate for test interpretation. The reference change value, useful to interpret changes in serial results, was ~9%. Conclusions. Our data show that strict analytical goals are needed for the clinical application of HbA1c measurements.

Revaluation of biological variation of HbA1c using an accurately designed protocol / F. Braga, A. Dolci, A. Ghezzi, M. Montagnana, F. Pagani, R. Paleari, L. Scapellato, G.C. Guidi, A. Mosca, M. Panteghini. - In: CLINICAL CHEMISTRY AND LABORATORY MEDICINE. - ISSN 1434-6621. - 49:Suppl. 1(2011), pp. S371-S371. ((Intervento presentato al 19. convegno IFCC - WordLab - EuroMedLab tenutosi a Berlin nel 2011 [10.1515/CCLM.2011.510].

Revaluation of biological variation of HbA1c using an accurately designed protocol

F. Braga;A. Dolci;R. Paleari;A. Mosca;M. Panteghini
Ultimo
2011

Abstract

Background. HbA1c has a key role for diagnosing diabetes and monitoring glycemic state. Knowledge of its biological variation (BV) is critical for result interpretation. As recently published results showed a marked heterogeneity of available BV data, we revaluated HbA1c BV using a well designed protocol. Methods. We took five blood specimens from 18 apparently healthy subjects (9 men and 9 women, ages 26-52 years) on the same day every two weeks for two months. Samples were stored at -80°C until analysis and assayed in duplicate in a single run by Roche Tina-quant Gen.2 immunoassay on the Integra 400 platform. Data were analyzed by the ANOVA. To assess the assay traceability to the IFCC reference method, we preliminarily carried out a correlation experiment on four blood samples. Results. The regression equation (Tina-quant = 1.05 IFCC reference method – 1.6 mmol/mol) confirmed the alignment of the employed assay. There were no differences in HbA1c values between men and women (global mean, 36 mmol/mol). Within- (CVI) and between-(CVG) subject BV were 2.5% and 7.1%, respectively. Desirable analytical goals derived from BV for imprecision (0.50 CVI), bias [0.25 (CVI 2 + CVG 2)1/2] and total error [1.65 (0.5 CVI) + 0.25 (CVI 2 + CVG 2)1/2] were 1.25%, 1.88%, and 3.94%, respectively. HbA1c had marked individuality, therefore the use of population-based reference limits could be inadequate for test interpretation. The reference change value, useful to interpret changes in serial results, was ~9%. Conclusions. Our data show that strict analytical goals are needed for the clinical application of HbA1c measurements.
Settore BIO/12 - Biochimica Clinica e Biologia Molecolare Clinica
2011
International Federation of Clinical Chemistry and Laboratory Medicine (IFCC)
European Federation of Clinical Chemistry and Laboratory Medicine (EFCC)
German Society of Clinical Chemistry and Laboratory Medicine (DGKL)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/165570
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