Validierung einer Routinemethode in der Qualitätskontrolle zur zuverlässigen Quantifizierung von Restzellen in gefrorenem Frischplasma aus einem Ansatz
Kristina Bedenk (Wiesentheid / DE), Sonja Dresel (Nürnberg / DE), Markus Biburger (Nürnberg / DE), Wiebke Handke (Nürnberg / DE), Marijke Weber-Schehl (Wiesentheid / DE), Axel Seltsam (Nürnberg / DE)
In our quality control of blood products, the residual cells in fresh-frozen plasma (FFP) are determined by three different methods. For routine measurement an efficient and accurate method to detect small numbers of residual leucocytes (rWBC), erythrocytes (rRBC) and platelets (rPLT) in a single-type assay is desirable. With the validation of the BD™ Plasma Count Kit, we have succeeded in establishing a flow cytometric measurement on the BD FACSLyric™, allowing simultaneous quantification.
The BD™ Plasma Count Kit (PC) was validated on the highly sensitive BD FACSLyric™ system using the BD FACSuite™ v1.5 software for determination of the absolute cell counts of rWBC, rRBC and rPLT in FFP. With this kit all three cell types are quantified by flow cytometry in a single tube with the use of defined counting beads. Validation of the specificity, stability, linearity and repeatability was performed. In absence of commercially available system controls, whole blood controls from in-house production were established. A quantification of residual cells in plasma was done in direct comparison with the existing methods (flow cytometry for rWBC, microscopy for rRBC, and impedance measurement via Sysmex for rPLT).
Specificity and recovery were demonstrated by spiking a defined numbers of cells in FFP. Furthermore, linearity was verified over a range of values relevant for routine use. The results of the inter- and intra-assay precision are consistent with the expected outcomes. Preanalytical procedures revealed that plasma samples can be stored at RT for up to 36h after initial collection. The validation demonstrated that 24 samples could be analysed in a single run. In addition, a comparative measurement of the routine methods with the Plasma Count was successfully performed. The difference of both measurements from mean did not exceed 1WBC/µl (LD plasma), 10 WBC/µl (NDL plasma), 550 RBC/µl and 4500 PLT/µl regarding testing individual samples.
Our data show that the PC assay is suitable for quality control of plasma after production according to the German guidelines. The use of this assay is expected to increase efficiency and sample throughput. In addition, a parallel testing of the existing methods for residual cell counting and the initial data collected in the routine with the plasma count assay is planned.
no conflict of interest