Browsing by Author "Inal, Tamer C."

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CHALLENGES IN VITAMIN D ANALYSIS
(SCIENDO, 2012-01-01) Serteser, Mustafa; Coskun, Abdurrahman; Inal, Tamer C.; Unsal, Ibrahim
Vitamin D is an important determinant for the regulation of calcium and phosphorus levels and mineralization of the bone. The most reliable indicator of vitamin D status is the measurement of plasma or serum 25OH-D concentration. Several studies reported discrepancies between the results of assays. These high variabilities in 25OH-D measurements are due to used assay technologies and lack of standardization against the reference materials. Different assays have been employed for the measurement of 25OH-D levels: Competitive Protein Binding Assays, immunoassays, direct detection methods. Choosing an assay platform is important both for clinical laboratory professionals and researchers, and several factors affect this process. Recently, liquid chromatography and tandem mass spectrometry is an alternative method to traditional assays and provides higher specificity and sensitivity than many assays
HOW ISO-15189 LABORATORY ACCREDITATION ASSURES PATIENT SAFETY?
(SOC MEDICAL BIOCHEMISTS SERBIA, 2012-01-01) Serteser, Mustafa; Coskun, Abdurrahman; Inal, Tamer C.; Unsal, Ibrahim
Healthcare is a complex profession involving the state-of-art technology and sometimes leading to unintentional harm. Many factors contribute to the occurrence of medical errors. Patient safety is one of the most serious global health issues and defined as the absence of preventable harm to a patient during any process of medical care. The frequency of medical errors is higher than expected. It has been concluded that the majority of medical errors are not because of the individual attitudes but mainly caused by faulty systems or processes leading the staff to make mistakes or fail to prevent them. Patient safety is a shared responsibility comprised of many stakeholders such as society, patients, nurses, educators, administrators, researchers, physicians, government and legislative bodies, professional associations and accrediting agencies. Medical laboratory services are essential to patient care and need to be available to meet the needs of both patients and caregivers. ISO-15189:2007 Medical Laboratories-Particular requirements for quality and competence, an internationally recognized standard containing requirements necessary for diagnostic laboratories to demonstrate their competence to deliver reliable laboratory services. It applies quality system requirements to the clinical laboratories with a strong focus on responsiveness to the needs of patients and clinicians. Applying the performance improvement strategies focusing on different phases in total testing process will significantly reduce the errors and therefore will improve the patient safety. In this way, laboratory professionals contribute to improvement of safety and outcomes of care by working in interdisciplinary approach manner.
Indirect Reference Intervals Estimated from Hospitalized Population for Thyrotropin and Free Thyroxine
(MEDICINSKA NAKLADA, 2010-01-01) Inal, Tamer C.; Serteser, Mustafa; Coskun, Abdurrahman; Ozpinar, Aysel; Unsal, Ibrahim
Aim To establish indirect reference intervals from patient results obtained during routine laboratory work as an alternative to laborious and expensive producing of their own reference range values according to international instructions. Methods All results for thyrotropin (TSH) and free thyroxine (T4) that were stored in our laboratory information system between 2004 and 2008 were included in this study. After a logarithmic transformation of the raw data, outliers were excluded. Non-parametric reference intervals were estimated statistically after visual observation of the distribution using stem-and-leaf plots and histograms. A standard normal deviation test was performed to test the significance of differences between sub-groups. Results There was no significant difference in serum TSH or free T4 concentrations between male and female participants. Because no differences were found within the time span of the study, combined reference intervals were calculated. Indirect reference values were 0.43- 3.93 mU/L for TSH and 11.98-21.33 pmol/L for free T4. Conclusion Using patient laboratory data values is a relatively easy and cheap method of establishing laboratory specific reference values if skewness and kurtosis of the distribution are not too large.
Reference interval of pregnancy-associated plasma protein-A in healthy men and non-pregnant women
(ELSEVIER, 2013-01-01) Coskun, Abdurrahman; Serteser, Mustafa; Duran, Sadik; Inal, Tamer C.; Erdogan, Birsen E.; Ozpinar, Aysel; Can, Ozge; Unsal, Ibrahim
Objective: The serum pregnancy-associated plasma protein-A (PAPP-A) concentration is a predictor of ischemic cardiac events and renal impairment. However, the reference interval of PAPP-A has not been determined. This study determined the reference interval of PAPP-A in men and non-pregnant women. Methods: The study enrolled 126 apparently healthy individuals (52 males and 74 females). The mean age of the men and women was 34.7 (range 20-66) years and 34.6 (range 18-65) years, respectively. Serum PAPP-A concentrations were determined using an ultrasensitive enzyme-linked immunoassay kit. Reference intervals were calculated using the bootstrap method. Results: The results for three subjects were outliers, so the reference interval of PAPP-A was calculated using the data for 123 subjects. PAPP-A was undetectable in 26 subjects. The reference interval of PAPP-A for men and women (with the 90\% confidence interval) was <22.9 ng/mL (19.7-23.3) and <33.6 ng/mL (25.2-36.7), respectively. In male subjects, serum PAPP-A levels of smokers {[}3.10 (UD, 7.30) ng/mL] were significantly lower than that of non-smokers {[}11.00 (UD, 24.4) ng/mL] (p < 0.001) and there was a positive correlation between serum PAPP-A levels and subjects' age (r=0.439