Browsing by Author "Aksungar, Fehime"

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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.
Association of maternal serum trace elements with newborn screening-thyroid stimulating hormone
(WALTER DE GRUYTER GMBH, 2020-01-01) Ucal, Yasemin; Serdar, Muhittin; Akin-Levi, Cansu; Yildirim-Keles, Zeynep Zulfiye; Turam, Cem; Kumru, Pinar; Muhcu, Murat; Eroglu, Mustafa; Aksungar, Fehime; Ozpinar, Aysel
Objectives: Trace elements are essential in thyroid functioning as they incorporate into biologically important enzymes as cofactors. The placenta can either activate or inhibit the transfer of maternal trace elements to the unborn. An imbalance of maternal trace elements in pregnancy may affect both maternal and newborn thyroid function. Methods: Blood samples from 315 lactating mothers were collected in the first 48 h after delivery and evaluated for selenium (Se), copper (Cu), manganese (Mn), and zinc (Zn) using flame atomic absorption spectroscopy (FAAS) and quadrupole inductively coupled plasma-mass spectrometer (ICP-MS). Thyroid hormones and auto-antibodies (thyroid-stimulating hormone (TSH), free T3 (fT3), free T3 (fT4), anti-thyroid peroxidase (anti-TPO), and antithyroglobulin (anti-TG)) were analyzed in maternal blood using an electro-chemiluminescence immunoassay (ECLIA). Between 48 and 72 postpartum hours, spot blood samples were used for newborn screening-TSH measurement. Correlation and multivariate analyses were performed to evaluate the effect of maternal trace element levels on newborn screening-TSH levels. Results: The medians (min-max) of maternal Se (45.16 mu g/L (21.28-79.04)), Cu (210.10 mu g/dL (117.04-390.64)), Mn (2.11 mu g/L (0.20-3.46)), and Zn (0.43 mg/L (0.24-0.66)) were determined. A positive correlation was detected between Zn and maternal TSH levels (r=0.12, p < 0.05). Newborn screening-TSH was significantly correlated with maternal Cu (r=0.14, p < 0.01). Similarly, Cu exhibited weak associations in clustering analysis while others shared common clusters with newborn-screening TSH. Conclusions: There was no significant association between most of the maternal serum trace elements and maternal thyroid hormone parameters, with an only exception between maternal Zn and maternal serum TSH. Finally, the association between maternal serum Cu levels and newborn screening-TSH levels may highlight the importance of maternal Cu levels on the newborn thyroid health.
What are the predominant parameters for Down's syndrome risk estimation in first- trimester screening: a data mining study
(WALTER DE GRUYTER GMBH, 2022-01-01) Kilercik, Mehem; Yozgat, Ihsan; Serdar, Muhittin A.; Aksungar, Fehime; Gogus, Sema; Solak, Semra; Kaya, Zelal Zuhal; Yayla, Ali Murat; Serteser, Mustafa
Objectives: This study aimed to evaluate the effect size of each parameter used in the first trimester Down Syndrome (DS) risk analyses by using multiple regression analysis techniques. Methods: This data mining study included data of 44,260 pregnant women screened at the Acibadem Labmed laboratories from 2010 to 2019. In this study, risk was calculated using the PRISCA software on the basis of nuchal translucency (NT), crown-rump length measurement, in vitro fertilization application, diabetes mellitus, Down Syndrome story, smoking, maternal age, and the level of maternal serum biochemistry markers including pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (hCG beta). Results: Forty-four thousand two hundred sixty risk analysis patients result data were re-investigate, and 851 (1.93\%) risk analysis results were found as positive. PAPP-A 747 (CI\%, 476-1,170) times, NT value 512 (CI\%, 343-764) times, DS story 21 times (CI\%, 6.7-63.2) and hCG beta value 7.01 (CI\%, 6.31-7.79) times affect the combined first-trimester risk analysis results. Conclusions: We have suggested that those accurate PAPP-A levels and NT levels evaluation are the most critical point of combined risk analysis and that the risk of free hCG beta levels after PAPP-A is essential as a biochemical test.