Quality assurance by a commercial flow cytometry method of leucodepletion of whole blood donations: initial application of universal testing and proposals for a batch‐release sampling plan

Abstract

We have used the Becton-Dickinson LeucoCOUNT test to monitor residual leucocytes in whole blood by flow cytometry following leucodepletion filtration. This test was found to be quick, robust and reliable, and allowed measurement of residual leucocytes down to 2.25 x 104 leucocytes per unit, which was found to match approximately the limit of filter proficiency. The results of testing > 1000 units showed a lognormal distribution with means between log(10) 4.864 (0.73 x 105) and log(10) 5.016 (1.04 x 105) leucocytes per unit in the three different homogeneous groups of filtered units studied. The numbers of units with residual leucocytes exceeding the 5 x 106 upper threshold were 1/577, 2/457 and 0/87 in these groups. The filtration processes were validated according to the published BEST working party guidelines and were well within the 99% confidence and 95% tolerance target for the 5 x 106 upper threshold set for the UK. A sampling plan based on British Standard BS 6001 with elimination of outliers by the extreme studentized deviate (Grubbs' test) was evaluated on random samples from these groups and has been adopted locally as a prospective batch-release criterion for release of leucodepleted blood.

Ultrastructural changes and activation differences in platelet concentrates stored in plasma and additive solution

“…To count residual WBCs after filtration, a newly developed flow cytometric analysis was used (LeucoCount). As reported recently, 14 this procedure is capable of measuring cell numbers as low as 500 WBC per mL. Lower numbers are reportable but of uncertain accuracy.…”

Comparative analysis of normal prion protein expression on human, rodent, and ruminant blood cells by using a panel of prion antibodies

“…In the clinical transfusion context, we have to determine the appropriateness of differential depletion or reduction of different blood components to enhance safety of blood, 60 and in a diagnostic or screening context the appropriateness of using certain antibodies, examining key blood cell types, and by using quantitative and diagnostic methods for PrP determination. In follow‐up studies, it will be important to define which components of blood may carry infectivity in different species and whether this is physically identifiable, allowing direct testing.…”

Infusion of P‐Capt prion‐filtered red blood cell products demonstrate acceptable in vivo viability and no evidence of neoantigen formation

“…Remaining WBC content was determined by high sensitivity fluorescence‐activated cell sorting analysis of propidium iodide–positive events using calibrated beads (Becton Dickinson, San Jose, CA) 22 …”