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 (×g). RPM, defined as the number of rotations of the centrifuge per minute, 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.

Endocan has been shown to be a marker for several cancers and may show degree of malignancy. The aim of this study is to assess serum levels of endocan before and after surgery on low-grade gliomas (LGGs). Endocan was assayed by commercially available enzyme-linked immunosorbent assay (ELISA) kits in a total of 19 patients and 12 controls. Serial serum samples were obtained before and after surgery (1st day, 1st week, and 1st month of surgery). Control samples were collected from cord blood during cesarean section. The results were compared with control brain tissues. Controls showed significantly lower serum endocan levels compared to before and after surgery (P < 0.05). There is a trend of increase in mean serum levels from before surgery and during the very early period after surgery (during first week); however, in the first month, mean serum levels became lower. Endocan, a vital molecule for angiogenesis, is highly expressed before and after surgery in LGGs, but long-term data is needed. Furthermore, future studies should include high-grade gliomas to discuss whether endocan is associated with recurrence and response to treatment.

Background: Unsuitable samples are common problem for laboratories. The blood collection tubes need to be validated or verified prior to their being used in the routine laboratory for reducing this situation. Objective: We aim to compare the technical qualifications of routinely used BD Vacutainer ^® Serum Separator Tubes™ II Advance Plus with BD Vacutainer ^® Barricor™ LH Plasma Tubes for local technical validation. Materials and methods: Apparently healthy 150 voluntary subjects were enrolled in the study. Samples were collected in two separated tubes by a single phlebotomist. Twelve quality indicators were used to compare these two different types of tubes for local technical validation. Differences (%) between them were calculated with the formula proposed by EFLM. In case of any difference of less than 1% for each indicator, the evaluated tube was considered as non-inferior. Results: Indicators, such as tubes with physical defects, that fail to create vacuum, not properly fitting into the blood collection device, under filling (10%), cracked tubes, tubes exterior surface contaminated with blood, hemolysed specimens, including fibrin strand/mass in the sample, red blood cell adhesion, poor/incomplete barrier formation were found non-inferior in Barricor™ tubes. White particulate matter (WPM) was observed in 24.6% of Barricor™. Therefore, the last indicator (tubes including gel/foreign material/WPM in sample after centrifugation) was found inferior for Barricor™. Conclusion: Technical local validation studies should be encouraged in terms of quality management. It was thought that WPM would not cause any interference in a properly filled tube. In addition to, Barricor™ was also found to be technically acceptable when evaluated through using all other indicators.

Uncertainty is an inseparable part of all types of measurements, that is, in metrology a measurement without uncertainty is not possible. Calculation of uncertainty increases the awareness of the certainty of measurement results. Reporting measurement uncertainty is mandatory in almost all industrial sectors but not in laboratory medicine. Test results without analytical uncertainty increases the diagnostic uncertainty, causing errors that could seriously affect patients health. To improve diagnostic certainty, we should calculate and upon request report measurement uncertainty to laboratory users (ISO 15189). In this mini-review, we summarized the theoretical perspective of uncertainty concept, its relation to Six Sigma and finally compared it with Total Error Method.