A Modified Method Counting of Leukoreduced Blood Components with Nageotte chamber abstract
Introduction: Counting assays with good performance characteristics are an essential elementof the process control of leukoreduction. Out of all the leukocyte enumeration techniques, theNageotte chamber counting technique has been found to be quite practical and cost effectivein a blood center setting, whereas, other techniques are cumbersome and labor intensive, withmore of a research interest.In the study reported here, we sought to demonstrate the effectiveness of incorporating thefixative 10%
Formaldehyde-citrate into a program of leukoreduction quality control under theassumption that, if successful, this simple method would allow samples to be either countedin batches at times when technical staff were available or shipped to a reference center forcounting when they were not.Method: For the purpose of this study, packed RBCs were leukoreduced in our TransfusionService’s laboratory. Whole blood was obtained from healthy volunteer blood donorsaccording to the Iranian regulations for blood donation and was collected into triple bags.Representative samples of leukoreduced packed RBCs and packed RBCs were collected forcounting by both the standard and 10% formaldehyde methods. A total of 12 packed RBCssamples were examined. Samples stored in 10%
Formaldehyde-citrate and refrigerated at 4degrees C for 3 days. All samples were assayed on the days of (0,1,3).Result: For WBC concentration range studied no significant changes in WBC concentrationsDays (0, 1, and 3) in modified method. The results showed significant quantitative changes inday (3) between two methods (P<0.05). The formalin-fixation methods yielded satisfactoryresults, 100% of samples had less than 1 x 106 residual WBC in modified method. Samplesstored in 10% formaldehyde and refrigerated at 4 degrees C lend themselves to countingwithout significant effects on the reproducibility of results.Conclusion: The aim of our study was to specify these events destruction post filtrationdepending on storage time .The method described herein, allows the collection andpreservation of samples for quality control and monitoring of leukoreduction at any timeduring the day or night or on weekends. It permits a more flexible quality-control programwithout increasing the workload during peak times or reduced-personnel shifts.Furthermore, the samples preserved using the formalin-fixation method can be shipped toother centers where residual WBC counting can be done more cost effectively.