engleski

Shorter centrifugation time could compromise sample quality

Introduction: According to the tube manufacturers recommended centrifugation conditions of serum samples are 10-15 minutes on 1800-2200 xg. If samples are not properly centrifuged, serum quality could be compromised due to the leftover fibrin in samples and higher degree of hemolyzed samples. The aim of this study was to investigate if shorter centrifugation time affects sample quality. Materials and methods: In Department of Clinical Chemistry, Sestre milosrdnice University Hospital Center serum samples were routinely centrifuged for 10 minutes at 2876 xg on Hettich Rotanta 46RSC (Hettich, Tuttlingen, Germany). In September 2017 for 10 days, time of centrifugation was reduced to 5 minutes. Samples with leftover fibrin were recorded from Architect c8000 and i2000 analyzers (Abbott, Abbott Park, IL, USA) as aspiration errors. Index of hemolysis (H) was measured on Architect c8000 for all serum samples. Samples with H index>0.5 were considered as hemolyzed. Proportion of samples with leftover fibrin and hemolysis was calculated against the total number of samples received from the laboratory information system. Results are presented as numbers and percentages. Proportions of hemolyzed and samples with aspiration errors were compared for 10 minutes and 5 minutes period with Chi-squared test for comparison of two proportions. Excel and MedCalc (v.11.5.1.0, Ostend, Belgium) were used for all calculations. P value <0.05 was considered as significant. Results: Proportion of samples with leftover fibrin was higher when centrifuged for 5 minutes than for 10 minutes (2.78% (161 out of total 5796) vs 2.14% (139 out of 6506), respectively, P=0.025). Higher proportion of hemolyzed samples was observed in 5 minutes centrifugation (4.60% (235 out of 5113) vs 3.65% (219 out of 5993) for 5 and 10 minutes, respectively, P=0.013). Conclusion: When samples are centrifuged for 5 minutes, higher proportions of hemolyzed and clotted samples are observed. Shorter centrifugation time compromises sample quality.

preanalytical phase ; centrifugation ; hemolysis ; turnaround time

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