2014, Cilt 12, Sayı 1, Sayfa(lar) 031-035 |
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Measurement Uncertainty of HbA2 in Thalasemia Screening |
Hamit Yaşar Ellidağ1, Esin Eren2, Özgür Aydın1, Funda Savaş1, Necat Yılmaz1 |
1Antalya Eğitim ve Araştırma Hastanesi, Biyokimya Laboratuvarı, Antalya, Türkiye 2Antalya Atatürk Devlet Hastanesi, Biyokimya Laboratuvarı, Antalya, Türkiye |
Keywords: Hemoglobin A2, high pressure liquid chromatography, uncertainty, thalassemia |
Objective: High Performance Liquid Chromatography (HPLC) is widely used to classify hemoglobin
fractions in screening of hemoglobinopathies. We, here in this study, detected the “measurement
uncertainty” of the pivotal parameter in thalassemia screening, namely HbA2; and assumed its value in
the laboratory test results.
Materials and Methods: HbA2 analysis was measured by HPLC analyser Tosoh HLC-723 G8
instrument, which works in cation exchange principle, in Antalya Research and Education Biochemistry
Laboratory. Measurement uncertainty calculations were made according to the Nordtest manuals, using
internal, and external quality control values.
Results: The measurement uncertainty for HbA2 was ±12.4% within a 95% coverage probability. The
cut-off value used in our laboratory for a positive screening result is 3.5%. Our cut-off value should
better be presented as 3.5±0.4% after the measurement uncertainty is included.
Conclusions: Although HbA2 measurement is important parameter in the screening of thalassemia,
the literature lacks studies of measurement uncertainty of this parameter. Each laboratory should define
their own measurement uncertainties not only to set their quality goals, but also in order to verify their
capability to aid in clinical decisions.
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