Pre-Analytical Parameters Affecting Vascular Endothelial Growth Factor Measurement in Plasma: Identifying Confounders.

Pre-Analytical Parameters Affecting Vascular Endothelial Growth Factor Measurement in Plasma: Identifying Confounders.

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BACKGROUND:Vascular endothelial growth factor-A (VEGF-A) is intensively investigated in various medical fields.However, comparing VEGF-A measurements is difficult because sample acquisition and pre-analytic procedures pet calming peanut butter differ between studies.We therefore investigated which variables act as confounders of VEGF-A measurements.METHODS:Following a standardized protocol, blood was taken at three clinical sites from six healthy participants (one male and one female participant at each center) twice one week apart.

The following pre-analytical parameters were varied in order to analyze their impact on VEGF-A measurements: analyzing center, anticoagulant (EDTA vs.PECT / CTAD), cannula (butterfly vs.neonatal), type of centrifuge (swing-out vs.fixed-angle), time before and after centrifugation, filling level (completely filled vs.

half-filled tubes) and analyzing method (ELISA vs.multiplex bead array).Additionally, intrapersonal variations over time and sex differences were explored.Statistical analysis was performed using a linear regression model.

RESULTS:The following parameters were identified as statistically significant independent confounders of VEGF-A measurements: analyzing center, roneverhart.com anticoagulant, centrifuge, analyzing method and sex of the proband.The following parameters were no significant confounders in our data set: intrapersonal variation over one week, cannula, time before and after centrifugation and filling level of collection tubes.CONCLUSION:VEGF-A measurement results can be affected significantly by the identified pre-analytical parameters.We recommend the use of CTAD anticoagulant, a standardized type of centrifuge and one central laboratory using the same analyzing method for all samples.