Evaluation of Manual Hb A1C Determination Methods in Diabetic Patients with Sickle Cell Trait


  • Nazar S. Haddad Department of Biochemistry Basrah Medical college Basrah Iraq


Background and Aim

     HbA1c is an irreversible non-enzymatic glycation at one or both NH2- terminal valines of the β –chain. Sickle hemoglobin, or HbS, has a valine for glutamic acid substitution at position 6 of the  β chain. The prevalence of sickle cell trait reported to be 2.5% in Basrah city. The hemoglobin A1C (A1C) test can lead to false outcomes resulting in over- treatment or under-treatment of diabetes in people with inherited hemoglobin variants.

   This study focus on the evaluation of sickle cell trait effect on HbA1c measurement by the minicolumn ion exchange resin methods and compare them  with Biorad Variant (HPLC method).the one of methods certified by national glycohemoglobin standardization program (NGSP)

Materials and Methods

    60 diabetic patients identified with sickle cell trait were recruited in this study .Blood sample collect in EDTA tubes and were assessed for hemoglobin A1c using 3 methods commercially available and most fequently used for routine investigations. Stanbio Glycohemoglobin (Pre- Filâ), HUMAN Glycohemglobin HbA1-Test ( Fast Ion Exchange Resin Separation Method ) ,and the Bio-Rad VARIANT Hemoglobin A1c (HPLC ) method


    Mean age group for patient were 39.6 yrs with their mean blood glucose level of about 203 mg/dl , the average glycohemoglobin was 9.1% measured by Biorad Variant, compare to 7.57% and 7.99% for both Stanbio method and Human Method respectively, which show statistically significant difference (p<0.05). It also had been found that average difference between both manual methods (|Stanbio and Human) and Automated method (biorad variant HPLC) about (1.5, 1.15) . These difference show a significant statistical correlation with hemoglobin S level with r =0.856; p value<0.001.


This study demonstrate the significant difference in Glycated hemoglobin measurements between different methods commercially available in local markets which had been shown to give false negative results in sickle trait patients when compared to those methods standardized by NGSP system. And recommend that such methods to be avoided in patient with sickle cell trait.


Schnedl WJ, Liebminger A, Roller RE, Lipp RW, Krejs GJ. Hemoglobin variants and determination of glycated hemoglobin (HbA1c). Diabetes Metab Res Rev. 2001 Mar-Apr; 17(2):94-8.

Burtis CA, Ashwood ER, Bruns DE. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Carbohydrates SAUNDERS, JUL-2005, 879 – 885.

Schnedl WJ, Lahousen T, Wallner SJ, Krause R, Lipp RW. Silent hemoglobin variants and determination of HbA(1c) with the high-resolution program of theHPLC HA-8160 hemoglobin analyzer. Clin Biochem. 2005 Jan;38(1):88-91.

Sickle Cell Trait and Other Hemoglobinopathies and Diabetes: Important Information for Physicians. National Diabetes Information Clearinghouse. www.diabetes.niddk.nih.gov

Bry L, Chen PC, Sacks DB. Effects of hemoglobin variants and chemically modified derivatives on assays for glycohemoglobin. Clin Chem. 2001 Feb; 47(2):153-63.

M.K. Hassan, J.Y. Taha, L.M. Al-Naama, N.M. Widad and S.N. Jasim. Frequency of haemoglobinopathies and glucose-6-phosphate dehydrogenase deficiency in Basra. East Mediterr Health J. 2003 Jan-Mar;9(1-2):45-54.

College of American Pathologists. CAP survey set GH2-B. Northfield, IL: CAP, 1999.

Bryśkiewicz ME, Majkowska L. Aspects of the standardization of glycated hemoglobin (HbA1c) measurement. Pol Merkur Lekarski. 2011 Feb;30(176):155-9.

Bry L, Chen PC, Sacks DB. Effects of hemoglobin variants and chemically modified derivatives on assays for glycohemoglobin. Clin Chem. 2001 Feb;47(2):153-63.

Alkasab FM, et al. The prevalence of sickle cell disease in Abu Al-Khasib district of southern Iraq. Journal of tropical medicine and hygiene, 1981, 84:77–80.

Obaid AD, Hassan MK, al-Naama LM. Sickle cell and G6PD deficiency genes in Abu al-Khasib district of southern Iraq. Medical journal of Basra University, 2001, 19:12–18.

Standards of Medical Care in Diabetes—2010. DIABETES CARE JAN 2010, VOLUME 33, SUPPLEMENT 1(4-10),.

Little RR, Roberts WL. A review of variant hemoglobins interfering with hemoglobin A1C measurement. J Diabetes Sci Technol. 2009 May 1;3(3):446-51.

Frank EL, Moulton L, Little RR, Wiedmeyer HM, Rohlfing C, Roberts WL. Effects of hemoglobin C and S traits on seven glycohemoglobin methods. Clin Chem. 2000 Jun;46(6 Pt 1):864-7.

Bissé E, Abragam EC. New less temperature-sensitive microchromatographic method for the separation and quantitation of glycosylated hemoglobins using anon-cyanide buffer system.J Chromatog 1985; 344: 81-91