Araştırma Çıktıları

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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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    Biological variations of ADAMTS13 and von Willebrand factor in human adults
    (CROATIAN SOC MEDICAL BIOCHEMISTS, 2014-01-01) Kilercik, Meltem; Coskun, Abdurrahman; Serteser, Mustafa; Inan, Deniz; Unsal, Ibrahim
    Background: The ultra-large von Willebrand factor (vWF) multimers are very active and must be degraded by ADAMTS13 for optimal activity. A severe functional deficiency of ADAMTS13 has been associated with thrombotic thrombocytopenic purpura. The correct interpretation of patient vWF and ADAMTS13 plasma levels requires an understanding of the biological variation associated with these analytes. In the present paper, we aimed to determine the biological variation of ADAMTS13 and vWF in human adults. Materials and methods: Blood samples were collected weekly from 19 healthy subjects for 5 consecutive weeks. vWF activity and antigenicity were determined using aggregometric and immunoturbidimetric methods. ADAMTS13 antigenicity and activity were determined by ELISA. Results: The within-subject biological variations for vWF activity and antigenicity were 8.06\% and 14.37\%, respectively, while the between-subject biological variations were 18.5\% and 22.59\%, respectively. The index of individuality for vWF activity was 0.44, while vWF antigenicity was 0.64. Similarly, ADAMTS13 activity and antigenicity within-subject biological variations were 12.73\% and 9.75\%, respectively, while between-subject biological variations were 9.63\% and 6.28\%, respectively. The ADAMTS13 indexes of individuality were 1.32 and 1.55, respectively. Conclusion: We report high biological variation and individuality in vWF antigenicity and activity levels. However, ADAMTS13 antigenicity and activity displayed high biological variation, but low individuality. Thus, population-based reference intervals may be useful for monitoring ADAMTS13 antigenicity and activity, but not for vWF, which displays high individuality. These findings should be considered when determining the reference interval and other clinical variables associated with ADAMTS13 and vWF levels.