Jump to ContentJump to Main Navigation
Show Summary Details
More options …

Clinical Chemistry and Laboratory Medicine (CCLM)

Published in Association with the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM)

Editor-in-Chief: Plebani, Mario

Ed. by Gillery, Philippe / Greaves, Ronda / Lackner, Karl J. / Lippi, Giuseppe / Melichar, Bohuslav / Payne, Deborah A. / Schlattmann, Peter

IMPACT FACTOR 2018: 3.638

CiteScore 2018: 2.44

SCImago Journal Rank (SJR) 2018: 1.191
Source Normalized Impact per Paper (SNIP) 2018: 1.205

See all formats and pricing
More options …
Volume 53, Issue 9


New trends in the long and puzzling history of HbA1c

Prof. Philippe Gillery
  • Associate Editor of Clinical Chemistry and Laboratory Medicine, Laboratory of Pediatric Biology and Research, University Hospital of Reims, 45, rue Cognacq-Jay, 51092 Reims cedex, France,
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2015-06-02 | DOI: https://doi.org/10.1515/cclm-2015-0413

The discovery that non-enzymatic glycation of proteins occurred in vivo with an increased intensity in diabetes mellitus has constituted a major step in human biology during the past 50 years. It has led to the identification of numerous post-translational modifications-derived products (PTMDPs), and to the demonstration of their involvement in the complications of various diseases, such as diabetes mellitus, atherosclerosis or chronic renal failure [1]. In the case of hemoglobin, the major glycated species has been defined as HbA1c, characterized by the non-enzymatic binding of glucose to the N-terminal extremities of HbA globin β-chains. HbA1c assay has been recognized for decades as a major tool in the monitoring and follow-up of patients with diabetes mellitus. Recently, its use has been extended to diabetes diagnosis and to other pathological situations [2, 3]. Thus, HbA1c is now recognized as a major biomarker used in clinical practice. However, the long and puzzling history of HbA1c is not yet finished.

Ten manuscripts published in this issue bring interesting additional information to this evolving area of laboratory medicine. Four of them are related to the necessary quality of HbA1c assays and to their current use in clinical practice. The evolution to an extended use of HbA1c assay in patient care has been made possible thanks to the increasing quality of field methods [4] and to the IFCC (International Federation of Clinical Chemistry and Laboratory Medicine) – managed international standardization of HbA1c assays which allows traceability to a validated and maintained reference system [5]. It must however be highlighted that, although being accepted at an international level, the implementation of the new reference system, implying especially a change of units and of recommendations, is still inconsistently implemented worldwide. This is well demonstrated in the European survey performed by Pentillä et al. published in this issue [6].

However, although being globally improved, the analytical performances of HbA1c assay methods are still unequal and determine directly the usefulness of the test in clinical use. Two papers published here demonstrate the impact of analytical performances of HbA1c assay methods on data management. Carlsen et al. point out the importance of taking into account the analytical quality of methods, especially measurement bias, when comparing benchmarking results from hospital practitioners or general practitioners [7]. Furthermore, Åsberg et al. highlight the importance of the determination of allowable total error and the consequences of establishing inappropriate thresholds in diabetes diagnosis [8]. In this respect, they confirm that the analytical quality of HbA1c assays is a key point for its optimal use in patient care.

Another topic covered here is the possibility of a substitutive use of HbA1c instead of the oral glucose tolerance test for screening abnormal glucose regulation in specific populations. Wang et al. suggest that HbA1c could constitute an interesting alternative solution in patients undergoing coronary angiography [9], reinforcing conclusions drawn from previous studies showing the interest of HbA1c assay for this indication in other cardiovascular diseases, such as acute ischemic stroke [10].

However, the semiological value of HbA1c is questioned in various clinical situations because of analytical and/or pathophysiological interferences [3]. This is especially the case in the presence of Hb variants, as illustrated here in five papers. This biological occurrence has constituted an important pitfall in clinical practice for many decades, first because the variant (and/or its glycated forms) may interfere with HbA1c determination, and second because it may alter the normal metabolism of hemoglobin or red blood cells (RBCs) [3, 11]. The major analytical issues related to HbA1c measurement in the presence of a variant have been progressively addressed by the development of assay methods that allow the separation of the most common variants and in the majority of cases a reliable HbA1c estimation, e.g., by ion-exchange HPLC, as illustrated in the evaluation study of a new system by Jaisson et al. [12], or by capillary electrophoresis [13, 14]. Besides, automated enzymatic or immunological methods avoid in most cases the interferences of the majority of Hb variants [15, 16]. A comprehensive summary of the currently determined interferences is available at the National Glycohemoglobin Standardization Program (NGSP) website [16]. Thus, most experimental data suggest that the analytical influence of Hb variants on HbA1c separation and quantification is of limited extent, or is at the least under control. However, this does not mean that all issues related to this subject have been addressed. For example, Ji et al. demonstrate here that β-thalassemia can still lead to misinterpreting HbA1c results, and highlight the importance of the optimal characterization and knowledge of every method with respect to interferences [17]. Moreover, less common variants may induce unexpected interferences with different impacts on the methods, as recently demonstrated elsewhere by Little et al. [18]. This is also illustrated here by the studies of Camacho Benitez et al. [19] and Bots et al. [20] in this issue. Both of them describe the interference of novel Hb variants (Hb Weesp and Hb Haelen in the first paper, Hb Valme in the second one) on HbA1c quantification by ion exchange HPLC.

Besides, a major recurrent problem is related to the glycation rates and kinetics of Hb variants. A prerequisite for the valid interpretation of HbA1c results in the presence of an Hb variant is the assumption that glycation rates of HbA and of the variant are comparable. This questioning is not an idle fancy. As a matter of fact, an impaired glycation process has been described in the case of a rare genetic variant, hemoglobin Görwihl [21, 22]. If glycation rates were different, then HbA1c calculated values would not reflect the actual level of glycemic balance, as the interpretation is scientifically based on HbA glycation criteria only. However, no consistent data about the kinetics of glycation of other Hb species is available so far. Former studies using incubation with radioisotopes suggested heterogeneous glycation rates of HbC, HbD and HbE compared to HbA [23], whereas some other short papers reported contradictory data, especially concerning HbC and HbS [24, 25]. Since then, no robust data have confirmed or infirmed differences in the respective glycation rates between these variants or others and HbA, even though a recent MALDI-TOF mass spectrometry study on in vitro glycated Hbs has suggested increased glycation rates of several Hb variants [26].

In this issue of the journal, Weykamp et al. show very interestingly that the glycation rates of various Hb variants could be close to that of HbA [27]. Using a methodological approach combining measurement of glycated hemoglobin by affinity chromatography, which is supposed to be free from interference of variants and to measure all glycated forms of hemoglobin, and of HbA1c by capillary electrophoresis, which allows HbA and HbA1c to be quantified separately and to calculate their specific ratio, the authors have shown that the two methods gave comparable results. It must however be highlighted that this study only brings indirect evidences of comparable glycation rates, and that the direct demonstration of similar in vivo glycation speeds is still lacking. However, waiting for confirmation of the data published here in a larger series of samples using additional analytical approaches, the topic of the glycation kinetics of variants seems to have been partly addressed.

It remains to determine whether the lifespan of RBCs is significantly affected by the presence of the variant, apart from the caricatural situations characterized by a patent hemolysis, such as in the presence of homozygous HbS or HbC. As a matter of fact, it is well known that HbA1c value is tightly related to the lifespan of RBCs which is assumed to be 120 days, even though it is not strictly the case in reality. Cohen et al. have clearly demonstrated that the mean age of circulating RBCs ranged from about 40 to 60 days, and that these variations in RBC survival were sufficient to lead to clinically relevant differences in HbA1c values for a given mean blood glucose [28].

Therefore, some important questions related to HbA1c metabolism and evaluation are still pending, and HbA1c and glycated proteins retain unsolved mysteries. Glycation, as well as the uncompletely known deglycation processes, may be more complicated than generally assumed. The opinion paper devoted to fructosamine-3-kinase published in this issue by Avemaria et al. [29] clearly demonstrates that other still poorly understood mechanisms influence the rate of Hb (and other protein) glycation, which have to be taken into account for optimal result interpretation in patients. Thus, there is still room for new concepts and exciting discoveries in the field of HbA1c and of the management of patients with diabetes mellitus, which is a stimulating perspective for scientists, clinicians and patients.

Author contributions: The author has accepted responsibility for the entire content of this submitted manuscript and approved submission.

Financial support: None declared.

Employment or leadership: None declared.

Honorarium: None declared.

Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.


  • 1.

    Jaisson S, Gillery P. Evaluation of nonenzymatic post-translational modification-derived products as biomarkers of molecular aging of proteins. Clin Chem 2010;56:1401–12.Web of ScienceCrossrefPubMedGoogle Scholar

  • 2.

    Gillery P. A history of HbA1c through Clinical Chemistry and Laboratory Medicine. Clin Chem Lab Med 2013;51:65–74.CrossrefGoogle Scholar

  • 3.

    Mosca A, Lapolla A, Gillery P. Glycemic control in the clinical management of diabetic patients. Clin Chem Lab Med 2013;51:753–66.PubMedCrossrefWeb of ScienceGoogle Scholar

  • 4.

    Gillery P, Dumont G, Vassault A. Evaluation of glycohemoglobin assays in France by national quality control surveys. Diabetes Care 1988;21:265–70.CrossrefGoogle Scholar

  • 5.

    Jeppson JO, Kobold U, Barr J, Finke A, Hoelzel W, Hoshino T, et al. Approved IFCC reference method for the measurement of HbA1c in human blood. Clin Chem Lab Med 2002;40:78–89.CrossrefGoogle Scholar

  • 6.

    Pentillä I, Pentillä K, Laitinen H, Holm P, Rauramaa R. Hemoglobin A1c reported in units and diagnostic cut offs in relation to the international recommendations. Clin Chem Lab Med 2015;53:e215–7.Web of ScienceGoogle Scholar

  • 7.

    Carlsen S, Thue G, Cooper JG, Røraas T, Gøransson LG, Løvaas K, et al. Benchmarking by HbA1c in a national diabetes quality register – does measurement bias matter? Clin Chem Lab Med 2015;53:1433–9.CrossrefWeb of ScienceGoogle Scholar

  • 8.

    Åsberg A, Odsœter IH, Carlsen SM, Mikkelsen G. Using the likelihood ratio to evaluate allowable total error – an example with glycated hemoglobin (HbA1c). Clin Chem Lab Med 2015;53:1459–64.CrossrefWeb of SciencePubMedGoogle Scholar

  • 9.

    Wang JS, Lee IT, Lee WJ, Lin SY, Fu CP, Lee WL, et al. Comparing HbA1c, fasting and 2-h plasma glucose for screening for abnormal glucose regulation in patients undergoing coronary angiography. Clin Chem Lab Med 2015;53:1441–9.Web of SciencePubMedCrossrefGoogle Scholar

  • 10.

    Wu S, Shi Y, Pan Y, Li J, Jia Q, Zhang N, et al. Glycated hemoglobin independently or in combination with fasting plasma glucose versus oral glucose tolerance test to detect abnormal glycometabolism in acute ischemic stroke: a Chinese cross-sectional study. BMC Neurology 2014;14:177–84.CrossrefWeb of SciencePubMedGoogle Scholar

  • 11.

    Jaisson S, Leroy N, Desroches C, Tonye-Libyh M, Guillard E, Gillery P. Interference of the most frequent haemoglobin variants on quantification of HbA1c: comparison between the LC-MS (IFCC reference method) and three routinely used methods. Diabetes Metab 2013;39:363–9.Web of ScienceCrossrefPubMedGoogle Scholar

  • 12.

    Jaisson S, Leroy N, Guillard E, Desmons A, Gillery P. Analytical performances of the D-100TM hemoglobin testing system (BioRad) for HbA1c assay. Clin Chem Lab Med 2015;53:1473–9.PubMedCrossrefGoogle Scholar

  • 13.

    Lin CN, Emery T, Little RR, Hanson SE, Rohlfing CL, Jaisson S, et al. Effects of hemoglobin C, D, E and S traits on measurements of HbA1c by six methods. Clin Chim Acta 2012;413:819–21.CrossrefWeb of ScienceGoogle Scholar

  • 14.

    Jaisson S, Leroy N, Meurice J, Guillard E, Gillery P. First evaluation of Capillarys 2 Flex Piercing® (Sebia) as a new analyzer for HbA1cassay by capillary electrophoresis. Clin Chem Lab Med 2012;50:1769–75.PubMedCrossrefWeb of ScienceGoogle Scholar

  • 15.

    Jaisson S, Desmons A, Renard B, Chevelle B, Leroy N, Gillery P. Analytical performances of a new enzymatic assay for hemoglobin A1c. Clin Chim Acta 2014;434:48–52.Web of ScienceCrossrefGoogle Scholar

  • 16.

    National Glycohemoglobin Standardization Program [Internet]. Available from : http://www.ngsp.org. Accessed 27 April, 2015.

  • 17.

    Ji L, Yu J, Zhou Y, Xia Y, Xu A, Li W, et al. Erroneous HbA1c measurements in the presence of β-thalassemia and common Chinese hemoglobin variants. Clin Chem Lab Med 2015;53:1451–8.PubMedCrossrefWeb of ScienceGoogle Scholar

  • 18.

    Little RR, La’ulu SL, Hanson SE, Rohlfing CL, Schmidt RL. Effects of 49 rare Hb variants on HbA1c measurements in eight methods. J Diabetes Sci Technol 2015 Feb 17, pii:1932296815572367.Google Scholar

  • 19.

    Camacho Benitez I, Chaves Lameiro P, Ropero P, Lázaro De la Osa JJ, González Fernández F, Moro Ortiz A. Hemoglobin Valme HBB: c124T > G: a new hemoglobin variant with diminished oxygen affinity causes interference in hemoglobin A1c measurement in an automated ion-exchange HPLC method. Clin Chem Lab Med 2015;53:e211–3.Google Scholar

  • 20.

    Bots M, Stroobants AK, Delzenne B, Soeters MR, de Vries JE, Weykamp C, et al. Two novel haemoglobin variants that affect haemoglobin A1cmeasurement by ion-exchange chromatography. Clin Chem Lab Med 2015;53:1465–71.Web of ScienceCrossrefGoogle Scholar

  • 21.

    Bissé E, Schauber C, Zorn N, Epting T, Eigel A, Van Dorsselaer A, et al. Hemoglobin Görwihl [a2b25(A2)Pro→Ala], an electrophoretically silent variant with impaired glycation. Clin Chem 2003;49:137–43.CrossrefPubMedGoogle Scholar

  • 22.

    Ito S, Nakahari T, Yamamoto D. Relationship between impaired glycation and the N-terminal structure of the Hb Görwihl [beta5(A2)Pro→Ala] variant. Hemoglobin 2010;34:151–6.Web of ScienceCrossrefGoogle Scholar

  • 23.

    Tegos C, Rahbar S, Blume K, Johnson C, Beutler E. Glycosylated minor C, D and E hemoglobins. Biochem Med 1981;26:121–5.CrossrefGoogle Scholar

  • 24.

    Aleyassine H. Glycosylation of hemoglobin S and hemoglobin C. Clin Chem 1980;26:526–7.PubMedGoogle Scholar

  • 25.

    Goujon R, Thivolet C. Glycation of hemoglobin C in the heterozygous state in diabetic patients. Diabetes Care 1994;17:247.CrossrefGoogle Scholar

  • 26.

    Lee BS, Jayathilaka GD, Huang JS, Vida LN, Honig GR, Gupta S. Analyses of in vitro nonenzymatic glycation of normal and variant hemoglobins by MALDI-TOF mass spectrometry. J Biomol Tech 2011;22:90–4.PubMedGoogle Scholar

  • 27.

    Weykamp C, Kemma E, Leppink S, Siebelder C. Glycation rate of haemoglobins S, C, D, E, J and G, and analytical interference on the measurement of HbA1c with affinity chromatography and capillary electrophoresis. Clin Chem Lab Med 2015;53:e207–10.Web of ScienceCrossrefGoogle Scholar

  • 28.

    Cohen RM, Franco RS, Khera PK, Smith EP, Lindsell CJ, Ciraolo PJ, et al. Red cell life span heterogeneity in hematologically normal people is sufficient to alter HbA1c. Blood 2008;112:4284–91.CrossrefWeb of ScienceGoogle Scholar

  • 29.

    Avemaria F, Carrera P, Lapolla A, Sartore G, Cristiano Chilelli N, Paleari R, et al. Possible role of fructosamine-3-kinase genotyping for the management of diabetic patients. Clin Chem Lab Med 2015;53:1315–20.Web of ScienceCrossrefGoogle Scholar

About the article

Published Online: 2015-06-02

Published in Print: 2015-08-01

Citation Information: Clinical Chemistry and Laboratory Medicine (CCLM), Volume 53, Issue 9, Pages 1297–1299, ISSN (Online) 1437-4331, ISSN (Print) 1434-6621, DOI: https://doi.org/10.1515/cclm-2015-0413.

Export Citation

©2015 by De Gruyter.Get Permission

Comments (0)

Please log in or register to comment.
Log in