title: Inter-method differences and commutability of control materials for HbA2 measurement.
abstract: 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.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Università degli Studi di Milano, Italy. andrea.mosca@unimi.it
authors.forename: A
authors.initials: A
authors.lastname: Mosca
authors.forename: R
authors.initials: R
authors.lastname: Paleari
authors.forename: V
authors.initials: V
authors.lastname: Scimè-Degani
authors.forename: L
authors.initials: L
authors.lastname: Leone
authors.forename: D
authors.initials: D
authors.lastname: Leone
authors.forename: G
authors.initials: G
authors.lastname: Ivaldi
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006443:Hemoglobin A2 / Q000032:analysis* / Q000592:standards; D006801:Humans; D012015:Reference Standards; D012044:Regression Analysis; D015203:Reproducibility of Results; D013789:Thalassemia / Q000175:diagnosis
chemical_list: D006443:Hemoglobin A2