The estimation of Hb A2 in the presence of Hb C or Hb E by reverse phase high performance liquid chromatography

Comparison of Two High-Pressure Liquid Chromatography Instruments Bio-Rad Variant-II and Tosoh HLC-723G11 in the Evaluation of Hemoglobinopathies

Hemoglobin High-performance liquid chromatography (Hb HPLC) is a standard first-line technique for diagnosis of thalassemia and hemoglobinopathies. We compared two HPLC systems for detection and quantification of normal and abnormal Hb fractions. EDTA samples from 100 normal healthy subjects and 107 subjects affected with hemoglobinopathies or carriers were analysed using HPLC systems Tosoh HLC-723G11 and Bio-Rad Variant-II. Retention time (RT) and area of peaks for HbA2, HbF and other structural variants were compared. In discrepant cases samples were run on Sebia Capillary zone electrophoresis (CZE) for confirmation of results (39 out of 107 cases with HbE, HbD Iran, Hb Lepore and HbQ). Measurement of HbA2 and HbF in normal samples and HbF in those with variant Hbs showed good correlation by both analyzers (R ² = 0.83, 0.9 and 0.99 respectively). HbE co-elutes with HbA2 in Bio-Rad. Correlation done using the apparent HbA2 concentration from Bio-Rad with (HbE + HbA2) from Tosoh G11 showed good correlation (R ² = 0.97). Correlation of HbS (Eluting at S-window at RT 3.11 min in Tosoh G11 and 4.33 min in Bio-Rad) as well as HbD Punjab (Eluting at D-window at RT 2.82 min in Tosoh G11 and 4.06 min in Bio-Rad) by both instruments was good. HbD Iran (Eluting at E-window at RT 2.69 min in Tosoh G11 and with HbA2 at 3.53 min in Bio-Rad); HbQ (Eluting at C-window at RT 3.78 min in Tosoh G11 and unknown window at 4.7 min in Bio-Rad), HbH (Eluting at P00 window at RT 0.13 min in Tosoh G11 and giving pre-integration peak in Bio-Rad), Hb Lepore (Eluting at P08 window at RT 2.67 min in Tosoh G11 and with HbA2 at 3.46 min in Bio-Rad) gave comparable results. Correlation with findings of CZE was done in few cases when needed. Two automated HPLC instruments demonstrated similar usefulness for screening patients for hemoglobinopathies. However, complex elution patterns as well as co-elution of variants like HbA2, HbE, Hb Lepore, HbD Iran (in Bio-Rad); HbD Iran and HbE (Tosoh G11) pose difficulty in interpretation. A complementary second method like CZE may be required.

The range of hemoglobin A(2) in hemoglobin E heterozygotes as determined by capillary electrophoresis

Capillary electrophoresis (CE) is capable of distinguishing hemoglobin E (HbE) from hemoglobin A(2) (HbA(2)), thus permitting quantification of HbA(2) in patients with HbE. In this study, routine samples submitted for evaluation of hemoglobinopathy that demonstrated HbE were studied by high-pressure liquid chromatography and CE. The data for 52 samples from adult HbE heterozygotes were compared with those for a control group consisting of 209 patients. The mean HbA(2) of patients with HbE trait was 3.4% (SD, 0.4%), which was significantly higher (P < .001) than the 2.6% (SD, 0.4%) for the control group. Seven samples from adults homozygous for HbE were also evaluated. The mean HbA(2) of HbE homozygotes was 4.4%, which was significantly greater (P < .001) than the HbA(2) values for the HbE heterozygotes. Data from these cases provide an estimate of the range of HbA(2) in patients with HbE when evaluated by CE.

Rapid diagnosis of thalassemias and other hemoglobinopathies by capillary electrophoresis system

Basic diagnosis of hemoglobinopathies can be performed by analysis of erythrocyte indices as well as by the separation and quantification of the common hemoglobin (Hb) fractions Hb A(2), Hb S, Hb C, Hb D, Hb E, and Hb F. This study used an automatic capillary zone electrophoresis system to diagnose various types of hemoglobinopathies common in the Thai population. A total of 459 adults were recruited, which consisted of normal, various types of thalassemia carriers, and thalassemia patients with different genotypes. Hb types and quantification of all Hb components were determined by an automated capillary zone electrophoresis. The automatic capillary electrophoresis system can separate and quantitate Hbs A, F, E, A(2), Constant Spring (CS), H, and Bart's in a way that is comparable with other Hb analysis methods. Moreover, the Hb A(2) peak can be distinguished clearly from the Hb E peak in individuals who carry Hb E. The slightly increased levels of Hb A(2), 3.5% +/- 0.4%, which is shown in the carriers of Hb E, confirm that Hb E is the silent phenotype of beta(+)-thalassemia.

Separation of hemoglobins and hemoglobin chains by high-performance liquid chromatography

This paper evaluates various high-performance liquid chromatographic (HPLC) procedures useful for the detection and evaluation of numerous hemoglobin abnormalities in adults and in newborn infants. Two major approaches are discussed. The first concerns the analyses of hemoglobins in red cell lysates by anion- and cation-exchange chromatography; this type of HPLC has great potential in a routine laboratory, as quantitative data for numerous abnormalities can readily be obtained. The second concerns the separation of globin chains by reversed-phase HPLC that is most useful for the identification of hemoglobinopathies in adults, newborns, and fetuses.