Browsing by Author "Avci, Esin"

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    An important source of preanalytical error in medical laboratories: centrifugation
    (WALTER DE GRUYTER GMBH, 2021-01-01) Sonmez, Cigdem; Gumus, Alper; Senes, Mehmet; Aykal, Guzin; Taneli, Fatma; Aksungar, Fehime; Avci, Esin; Coskun, Cihan; Cinaroglu, Ipek; Colak, Ayfer; Eker, Pinar; Gucel, Funda; Hakligor, Aylin; Inal, Berrin Bercik; Orhan, Bagnu; Yilmaz, Canan
    Centrifugation separates particles within the specimen according to their shape, dimensions, and density and basically can be defined as a separation method. The centrifuge is an essential device in medical laboratories to prepare the serum, plasma, and urine samples for analysis. It is basically an electric device composed of the stationary (motor) and the motile (rotor) part. The centrifugation depends on two main variables: relative centrifugal force (RCF) and centrifugation time. The physical impact separating the specimen into its components in the centrifuge known as RCF is expressed as the multiples of gravitational acceleration (xg). RPM, defined as the number of rotations of the centrifuge perminute, shows the speed of the centrifuge. RCF value can be calculated by using RPM, and the centrifuge radius. Because models and sizes of centrifuges vary considerably, the use of gravity (g) forces instead of RPM is suggested. The centrifuges can be classified according to their usage, speed, technical specifications, and rotor type. An accurate and precise centrifugation process is essential to prevent errors in the preanalytical phase. The purpose of this document is to ensure the standardization of a good, precise protocol for the centrifugation process among the medical laboratories.
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    Determining biological variation of serum parathyroid hormone in healthy adults
    (CROATIAN SOC MEDICAL BIOCHEMISTRY \& LABORATORY MEDICINE, 2019-01-01) Ercan, Mujgan; Akbulut, Emis Deniz; Avci, Esin; Yucel, Cigdem; Oguz, Esra Firat; Turhan, Turan; Serdar, Muhittin
    Introduction: Measurement of parathyroid hormone (PTH) is essential in the investigation and management of calcium metabolism disorders. To assess the significance of any assay result when clinical decision making biological variation (BV) of the measurand must be taken into consideration. The aim of the present study is determining the BV parameters for serum PTH. Materials and methods: Blood samples were taken at weekly intervals from 20 healthy subjects for ten weeks in this prospective BV study. Serum ``intact PTH{''} concentrations were measured with electrochemiluminescence method. Biological variation parameters were estimated using the approach proposed by Fraser. Results: The values of within-subject biological variation (CVI), between-subject biological variation (CVG), analytical variation (CVA), reference change value (RCV) and individuality index (II) for serum PTH were 21.1\%, 24.9\%, 3.8\%, 59.4\% and 0.8\%, respectively. Within-subject biological variation and CVG were also determined according to gender separately
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    Evaluation of four different HPLC devices for hemoglobinopathy screening
    (WALTER DE GRUYTER GMBH, 2021-01-01) Karadag, Mujgan Ercan; Akbulut, Emis Deniz; Avci, Esin; Oguz, Esra Firat; Kader, Saadet; Abusoglu, Gulsum; Serdar, Muhittin; Yamaz, Fatma Meric
    Objective: Hemoglobinopathies are a common public health problem in Turkey. In the screening of these disorders in population, cation-exchange high performance liquid chromatography (HPLC) is accepted as the gold standard method. In this study, the aim was to assess four different HPLC devices used in hemoglobinopathy screening. Materials and methods: A total of 58 blood samples were analyzed with four different HPLC methods (Bio-Rad variant II, Agilent 1100, Tosoh G8 and Trinity Ultra2 trademarks). Results: The comparison study demonstrated a good correlation between the results of each HPLC analyzer and the reference value obtained by averaging all the HbA(2) results belonging to the methods tested in the study {[}(Tosoh G8 (r=0.988), Bio-Rad variant II (r=0.993), Agilent 1100 (r=0.98) and Trinity Ultra2 (r=0.992)]. HbA(2) determination in the presence of HbE was interfered in both BioRad variant II and Tosoh G8. Conclusion: The analyzers were found to have compatible HbA(2) results but with accompanying different degrees of proportional and systematic biases. HPLC analyzers may be affected by different hemoglobin variants at different HbA(2) concentrations, which is an important point to take into consideration during the evaluation of HbA(2) results in thalassemia screening.