Quantitation of Hemoglobin A<sub>2</sub>: An Interlaboratory Study

Schmidt, Robert M.; Brosious, Effie M.

doi:10.1093/ajcp/71.5.534

Cited by 9 publications

(4 citation statements)

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“…All patients attended the clinics regularly and their hematological data were generated using routine clinical methods. HbF and HbA 2 were measured by alkali denaturing electrophoresis (9, 10). The presence of HbS was confirmed by acid electrophoresis.…”

Section: Patientsmentioning

confidence: 99%

β‐Globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in Lebanon

Inati¹,

Taher

Koussa³

et al. 2003

European J of Haematology

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Sickle cell disease (SCD) is an inherited autosomal recessive disorder of the beta-globin chain. Despite the fact that all subjects with SCD have the same single base pair mutation, the severity of the clinical and hematological manifestations is extremely variable. This study examined for the first time in Lebanon the correlation between the clinical manifestation of SCD and the beta-globin gene haplotypes. The haplotypes of 50 patients diagnosed with SCD were determined using polymerase chain reaction amplification of fragments containing nine polymorphic restriction sites around and within the epsilon-Ggamma-Agamma-psibeta-delta-beta-globin gene complex. Most reported haplotypes were found in our population with the Benin haplotype as the most prevalent one. When the patients were divided according to their HbF levels into three groups (Group A: HbF < 5%, Group B: HbF between 5 and 15%, and Group C: HbF > 15%), surprisingly, the highest levels of HbF were associated with the most severe clinical cases. Our findings suggest that fetal hemoglobin levels are important but not the only parameters that affect the severity of the disease. In addition, the high levels of HbF in patients with CAR haplotypes did not seem to ameliorate the severity of symptoms, suggesting that genetic factors other than haplotypes are the major determinants of increased HbF levels in Lebanon.

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Section: Patientsmentioning

confidence: 99%

β‐Globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in Lebanon

Inati¹,

Taher

Koussa³

et al. 2003

European J of Haematology

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“…Analytic methods to quantify HbA 2 include electrophoresis at an alkaline pH, high-performance liquid chromatography (HPLC), and tandem mass spectrometry. 2 Studies performed in the 1970s [3][4][5][6] showed poor precision for HbA 2 quantification methods based on electrophoresis. Steinberg and Adams 1 concluded that although electrophoresis at an alkaline pH with densitometric tracings of electrophoretograms for quantification of HbA 2 was an ideal clinical laboratory method from an ease-of-use perspective, it was inaccurate.…”

Section: Introductionmentioning

confidence: 99%

Quantification of HbA₂in Patients With and Without β-Thalassemia and in the Presence of HbS, HbC, HbE, and HbD Punjab Hemoglobin Variants

Higgins¹,

Khajuria²,

Mack³

2009

Am J Clin Pathol

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We studied whether problems quantifying hemoglobin A(2) (HbA(2)) could be resolved by using capillary electrophoresis. HbA(2) was quantified on whole blood samples from patients with and without beta-thalassemia trait and patients heterozygous for HbE, HbS, HbC, and HbD Punjab using the VARIANT II beta-thalassemia (Bio-Rad, Hercules, CA) and Capillarys 2 (Sebia, Norcross, GA). HbA(2) results in patients with and without beta-thalassemia trait were lower with the Capillarys 2 system. Reasonable HbA(2) results were obtained for patients with HbD Punjab and HbE traits on the Capillarys 2. HbA(2) results for patients with HbS, heterozygous and homozygous, were similar by both methods. Interference due to coelution for HbA(2) results for patients with HbC trait was noted on the Capillarys 2. Between-day imprecision on the VARIANT II is less than that for the Capillarys 2 system. The Capillarys 2 is superior to the VARIANT II for quantifying HbA(2) in the presence of HbE and HbD Punjab traits. The Capillarys 2 offers only slight advantages over the VARIANT II for quantifying HbA(2) in the presence of heterozygous and homozygous HbS. The Capillarys 2 gives inferior HbA(2) results for patients with HbC trait.

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“…Indeed, the few data available from external quality assessment schemes on HbA 2 determination by routine laboratories demonstrate that data obtained by different laboratories using the same technique are often quite dispersed (20)(21)(22). Most of the variability is probably due to discrepancies in the calibration of the techniques, although direct evidence about how calibration is performed and which materials are used is hard to ascertain.…”

Section: Discussionmentioning

confidence: 99%

Inter-Method Differences and Commutability of Control Materials for HbA2 Measurement

Mosca¹,

Paleari²,

Scimè-Degani³

et al. 2000

CCLM

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The intermethod variability of control materials and patient blood samples for the measurement of hemoglobin A2 (HbA2) were compared. A set of 54 blood samples and 10 control materials were analyzed in duplicate by HPLC and microcolumn methods. For each set of methods the distances of the materials from the regression line of patient blood results (expressed as normalized residuals) were calculated. Four out of ten controls had normalized residuals exceeding three standard deviations from the regression line. Moreover, total Hb and Hb derivatives analysis proved that only a minority of the controls could be considered similar to patients' blood samples. Intermethod calibration performed "a posteriori" by the two best performing control materials improved intermethod variability among all the five tested methods. We conclude that the use of high resolution HPLC methods together with appropriate commutable control materials allows for better harmonization of results in the field of diagnosis of hemoglobin disorders in research and clinical practice.

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Quantitation of Hemoglobin A₂: An Interlaboratory Study

Cited by 9 publications

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β‐Globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in Lebanon

β‐Globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in Lebanon

Quantification of HbA₂in Patients With and Without β-Thalassemia and in the Presence of HbS, HbC, HbE, and HbD Punjab Hemoglobin Variants

Inter-Method Differences and Commutability of Control Materials for HbA2 Measurement

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Quantitation of Hemoglobin A2: An Interlaboratory Study

Cited by 9 publications

References 0 publications

β‐Globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in Lebanon

β‐Globin gene cluster haplotypes and HbF levels are not the only modulators of sickle cell disease in Lebanon

Quantification of HbA2in Patients With and Without β-Thalassemia and in the Presence of HbS, HbC, HbE, and HbD Punjab Hemoglobin Variants

Inter-Method Differences and Commutability of Control Materials for HbA2 Measurement

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Quantitation of Hemoglobin A₂: An Interlaboratory Study

Quantification of HbA₂in Patients With and Without β-Thalassemia and in the Presence of HbS, HbC, HbE, and HbD Punjab Hemoglobin Variants