RESUMO
OBJECTIVES: We evaluated the performance of a novel capillary isoelectric focusing (CIEF) application for hemoglobinopathy screening on the recently introduced V8 E-Class platform. METHODS: Analytical performance of the V8 E-Class was evaluated and included assessment of hemoglobin A2 (HbA2) imprecision; linearity for HbA2, fetal hemoglobin (HbF), and sickle hemoglobin (HbS); and carryover for HbS. Furthermore, a method comparison with the Minicap Flex Piercing (Sebia, Lisses, France), the Variant Classic (Bio-Rad Laboratories, Hercules, CA), and the G8 (Tosoh Europe, Amsterdam, the Netherlands) was done to assess analytical and clinical concordance. RESULTS: Total HbA2 imprecision was 3.26% and 3.14% for normal and elevated HbA2 controls and 5.16% and 3.58% for a normal and a heterozygous HbS patient sample, respectively. HbA2, HbF, and HbS showed acceptable linearity, and no carryover was observed. The method comparison showed good analytical concordance (r > 0.95) except for a homozygous HbS subset (r = 0.532-0.704). A comparable phenomenon was seen for the clinical concordance with good agreement in samples without variants (weighted κ > 0.80) but poorer agreement in HbS samples (κ < 0.30). CONCLUSIONS: Good analytical performance was demonstrated for this novel CIEF application for hemoglobinopathy screening. Method comparison showed generally good correlation but highlights the need for standardization. Finally, software optimization could further add to its use for routine hemoglobinopathy screening.
Assuntos
Hemoglobina Fetal/análise , Hemoglobina A2/análise , Hemoglobina Falciforme/análise , Hemoglobinopatias/diagnóstico , Eletroforese Capilar/instrumentação , Eletroforese Capilar/métodos , Humanos , Focalização Isoelétrica/instrumentação , Focalização Isoelétrica/métodos , Reprodutibilidade dos TestesAssuntos
Ácido Aspártico/genética , Diabetes Mellitus Tipo 2/diagnóstico , Hemoglobinas Glicadas/análise , Testes Hematológicos , Hemoglobina A2/genética , Histidina/genética , Adulto , Cátions/química , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Diabetes Mellitus Tipo 2/genética , Feminino , Variação Genética/genética , Hemoglobinas Glicadas/genética , HumanosRESUMO
We report the case of a 56-year-old Caucasian woman in whom hemoglobinopathy screening was triggered following an aberrant Hb A1c analysis. Preliminary diagnosis of the hemoglobin (Hb) variant was obtained through cation exchange high performance liquid chromatography (HPLC) and gel electrophoresis. DNA analysis confirmed the presence of Hb J-Amiens [ß17(A14)LysâAsn; HBB: c.[54G > C or 54G > T)]. However, an unbalanced ratio between wild type and mutant signal after direct sequencing and a lower than expected percentage of this Hb variant led to the suggestion of a mosaic expression. Furthermore, different methods [capillary zone electrophoresis (CZE), cation exchange HPLC and boronate affinity] were tested to study the possible interference of this variant with Hb A1c measurements. These investigations showed a clinically relevant difference between the methods tested. Hb A1c analysis may lead to the discovery of new Hb variants or mosaicism for previously described Hb variants. This may have genetic consequences for the offspring of carriers and brings about the question of partner testing.
