Browsing by Author "Gulbahar, Ozlem"

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    A short guideline on chronic kidney disease for medical laboratory practice
    (WALTER DE GRUYTER GMBH, 2016-01-01) Abusoglu, Sedat; Aydin, Ilknur; Bakar, Funda; Bekdemir, Tan; Gulbahar, Ozlem; Islekel, Huray; Ozarda, Yesim; Pektas, Macit; Pir, Kamil; Portakal, Oytun; Serdar, Muhittin; Turhan, Turan; Yucel, Dogan; Zengi, Oguzhan
    Chronic kidney disease (CKD) is asymptomatic in the early stage. Kidney function might be lost 90\% when the symptoms are overt. However, in case of early detection, progression of the disease can be prevented or delayed. If not detected it results in end stage renal disease. Therefore, the level of awareness about CKD should be increased. The role of medical laboratory is utmost important for the diagnosis and staging of CKD. In this paper, the main tasks of the laboratory specialists are described and the outlines are as follows. Creatinine assays should be traceable to internationally recognised reference materials and methods, specifically isotope dilution mass spectrometry. When reporting the creatinine result, eGFR should also be reported in adult (> 18 years) population. A warning expression should be included in the report form if eGFR result is <60 mL/min/1.73 m(2). eGFR values should be expressed quantitatively up to 90 mL/min/1.73 m(2) by CKD-EPI equation. Above 90 mL/min/1.73 m(2), eGFR values can be expressed quantitatively or >90 mL/min/1.73 m2. eGFR equations of the adult population should not be used for pediatric population. Different equations utilizing also patient height should be used. The enzymatic creatinine assay should be preferred. eGFR based on cystatin C can be used for confirmation in the pediatric population. Cystatin C measurements, at least when eGFR based on creatinine is not reliable and for confirmation should be encouraged. Proteinuria or albuminuria values should be measured in spot samples and reported in proportion to creatinine.
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    Comparison of four immunoassay analyzers for relationship between thyroid stimulating hormone (TSH) and free thyroxine (FT4)
    (TURKISH BIOCHEM SOC, 2015-01-01) Serdar, Muhittin A.; Ispir, Emre; Ozgurtas, Taner; Gulbahar, Ozlem; Ciraci, Zahid; Pasaoglu, Hatice; Kurt, Ismail
    Objective: There is an inverse log/linear relationship between TSH and FT4 due to the negative feedback of these hormones on the pituitary. The objective of our study was to compare this relationship of TSH and FT4 between four different immunoassay analyzers. Methods: In our study, four data sets obtained from the database of four different hospital laboratories each using only a single method of measurement was used to evaluate this relationship between TSH and FT4. These data sets with their assay methods include: 21.102 test results measured by Modular E170 Analyzer (Roche Diagnostics, Germany), 20.241 test results measured by Access DxI 800 Unicel (Beckman Coulter, USA), 22.444 test results measured by Architect i2000sr (Abbott Laboratories, Abbott Park, Illinois, U.S.A) and 20.200 test results measured by ADVIA Centaur XP (Siemens Diagnostics, Tarrytown, NY). Inverse logarithmic relationship were determined from each data sets and compared between analyzers. Results: The correlation coefficients were -0.439 {[}95\% CI, (-0.450)- (-0.428)], -0.488 {[}95\% CI, (-0.498)- (-0.478)], -0.353 {[}95\% CI, (-0.364)- (-0.342)], -0.430 {[}95\% CI, (-0.441)- (-0.419)] for DxI 800 Unicel, Modular E 170, Architect i2000sr and ADVIA Centaur XP, respectively. In our study, all immunoassay analyzers showed poor correlation in a concentration range of TSH between 1.0 to 10.0 uIU/mL and the inverse log/linear relationship was not observed. Inverse relationship between TSH and FT4 is the result of negative thyroid pituitary hypothalamic feedback mechanism and this relationship is important especially in the diagnosis and treatment of hypo and hyperthyroidism. In data sets obtained from four different immunoassay analyzers, poor and statistically different correlation was observed between analyzers at TSH values ranged from 1.0 to 10.0 uIU/mL compared with FT4. Conclusion: These variations between analyzers may affect the clinical decisions especially in the evaluation of subclinical hypothyroidism, clinicians and laboratory specialists should be aware of these situation.