Abnormal haemoglobins, Hb Takamatsu and Hb G-Szuhu, detected during the analysis of glycated haemoglobin (HbA_1C) by high performance liquid chromatography

Abstract

Background-During medical checkups of two unrelated female outpatients during their annual health examination and one male inpatient suVering from cardiac failure the glycated haemoglobin (HbA 1C ) concentrations measured by high performance liquid chromatography (HPLC) were low, in spite of normal fasting plasma glucose concentrations. However, HbA 1C concentrations measured by latex immunoagglutination and fructosamine concentrations were within the normal range. Method-Investigations were performed to elucidate the reasons for these discrepancies. Results-Abnormal haemoglobins, HbTakamatsu and Hb G-Szuhu, were found. The HPLC chromatogram showed an additional peak near HbA 1a+b , which resulted in falsely low HbA 1C concentrations. Isoelectric focusing analysis of the patients' haemoglobin disclosed abnormal haemoglobins, which migrated faster than normal HbA 1 in the two female patients and slower in the male patient. The cDNA sequence and amino acid analyses of the haemoglobin -chains and -chains indicated the presence of the haemoglobin variant 120 Lys→Gln in the two female patients and 80 Asn→Lys in the male patient; that is, Hb Takamatsu and Hb G-Szuhu. Conclusions-These cases show how these silent haemoglobin variants can result in falsely low HbA 1C concentration readings when using HPLC. (J Clin Pathol 2000;53:854-857)

Silent haemoglobin variants and determination of HbA1c with the HPLC Bio-Rad Variant II

“…Several haemoglobin variants are known to interfere with measurement of HbA 1c by HPLC, 4 and an increasing number of interfering haemoglobin variants have been reported. 23 Only a few haemoglobin variants are known to affect HbA 1c results in immunoassays. 4 5 Boronate affinity methods measure glycohaemoglobin regardless of the glycation site.…”

Falsely high glycated haemoglobin [HbA1C] because of haemoglobin OSU-Christiansborg

“…Most of them are accompanied by changes in electric charge because of the substitution of amino acids, resulting in an abnormal HPLC elution pattern. Haemoglobin Takamatsu, HbG‐Szuhu (Moriwaki et al. , 2000), HbC, HbS, HbO Padova, HbJ‐Meerut, Hb Riyadh, HbJ‐Baltimore, Hb Camden, HbJ‐Lome, Hb Ube‐2, Hb Rambam (Schnedl et al.…”

Factitious Biochemical Measurements Resulting From Hematologic Conditions

“…However, HbA 1c measurement by highperformance liquid chromatography (HPLC)-based assays is inaccurate in the presence of some structurally abnormal hemoglobins. 63,70,71,[77][78][79]87,88 The extent of interference varies with the specific commercial HPLC method used and the type of abnormal hemoglobin.…”

“…Some hemoglobin variants result in underestimation of HbA 1c , eg, Hb Takamatsu, HbG Szuhu, 71 HbC, HbS, HbO Padova, 72 HbJ Meerut, 73 Hb Riyadh, 74 HbJ Baltimore, Hb Camden, HbJ Lome, Hb Ube-2, Hb Etobicoke, 75 Hb Görwihl, 76 and Hb Rambam. 70 Other variants result in overestimation of HbA 1c , eg, Hb Raleigh, 80 Hb Okayama, 70 Hb Graz, 63 HbK Woolwich, 77 Hb Osu-Christiansborg, 78 Hb Sherwood Forest, Hb South Florida, and Hb Niigata.…”