HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (14) Citing Articles via Google Scholar Google Scholar Articles by Roberts, N. B. Articles by Green, B. N. Search for Related Content PubMed PubMed Citation Articles by Roberts, N. B. Articles by Green, B. N. Related Collections Proteomics and Protein Markers Endocrinology and Metabolism

Long-Term Evaluation of Electrospray Ionization Mass Spectrometric Analysis of Glycated Hemoglobin

¹ Department of Clinical Chemistry, Royal Liverpool University Hospital, Liverpool L7 8XP, United Kingdom.

² Micromass (UK) Ltd., Wythenshawe, Manchester M239LZ, United Kingdom.
^a Author for correspondence. Fax 44-0151-706-5813; e-mail n.b.roberts{at}liverpool.ac.uk.

Background: Electrospray ionization mass spectrometry (ESIMS) has been successfully applied to the identification of hemoglobin (Hb) variants and the presence of glucose adducts (mass difference of 162 Da) on the separate Hb and ß chains. To establish the potential of ESIMS as a routine and/or a reference method for the quantification of glycohemoglobin (HbA1c), we carried out a detailed evaluation over a 4-month period in a routine laboratory environment.

Methods: We optimized a procedure using ESIMS suitable for the routine quantitative analysis of HbA1c. We determined reliability and reproducibility over 4 months and assessed the potential for automated sample injection. We then compared values of 1022 blood samples from diabetic patients with a routine HPLC-based ion-exchange procedure (HA-8140; Menarini).

Results: Results of HbA1c measurement by ESIMS were available within 3 min. The analytical imprecision (CV) was 1.6–5.0% for both manual and automated injections. Data collection over the m/z 980-1400 range confirmed lower glycation of the chain relative to the ß chain (0.66:1). Only one glycation was observed per globin chain. The overall glycohemoglobin (i.e., the average of - and ß-chain glycations) measured by ESIMS (x) on 1022 blood samples was lower than by HPLC (y): y = 1.0432x + 0.4815. However, the ß-chain glycation measured by ESIMS was up to 20% higher than the value measured by ion-exchange HPLC and showed a close conformity, particularly at 5–10% HbA1c, with the ion-exchange Diabetes Control and Complications Trial (DCCT)-corrected and the United Kingdom National External Quality Assessment Scheme DCCT mean return values.

Conclusions: ESIMS provides a precise measurement of HbA1c and, in particular, glycation of the ß chain. The method is robust and could be proposed as a procedure to substantiate HbA1c measurement and/or calibration.

The following articles in journals at HighWire Press have cited this article:

				N. Ahmed, R. Babaei-Jadidi, S. K. Howell, P. J. Thornalley, and P. J. Beisswenger Glycated and Oxidized Protein Degradation Products Are Indicators of Fasting and Postprandial Hyperglycemia in Diabetes Diabetes Care, October 1, 2005; 28(10): 2465 - 2471. [Abstract] [Full Text] [PDF]