Multicenter evaluation of two flow cytometric methods for counting low levels of white blood cells

• Published in: Transfusion (Philadelphia, Pa.) Pa.), 2004-09, Vol.44 (9), p.1319-1324
• Main Authors: Dijkstra-Tiekstra, Margriet J., Van Der Meer, Pieter F., Pietersz, Ruby N.I., De Wildt-Eggen, Janny
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood Component Transfusion; Blood Platelets; Blood. Blood and plasma substitutes. Blood products. Blood cells. Blood typing. Plasmapheresis. Apheresis; Erythrocytes; Flow Cytometry - instrumentation; Flow Cytometry - methods; Humans; Leukocyte Count; Medical sciences; Plasma; Transfusions. Complications. Transfusion reactions. Cell and gene therapy
• ISSN: 0041-1132; 1537-2995
• DOI: 10.1111/j.0041-1132.2004.04040.x

BACKGROUND:  Flow cytometric methods can be used to count residual white blood cells (WBCs) in WBC‐reduced blood products, which should contain fewer than 1 × 106 WBCs per unit (∼3.3 WBCs/µL). In this study two flow cytometric methods for counting WBCs under routine conditions in nine laboratories were evaluated. STUDY DESIGN AND METHODS:  Panels of red blood cells (RBCs), platelets (PLTs), and plasma were prepared containing 33.3, 10.0, 3.3, 1.0, and 0.3 WBCs per µL and counted with flow cytometric methods (either LeucoCOUNT, BD Biosciences, four laboratories; or LeukoSure, Beckman Coulter, five laboratories). Requirements were that at the level of 3.3 WBCs per µL, coefficient of variation was ≤20 percent and accuracy was ≥80 percent. Routine flow cytometric quality control (QC) data of WBC‐reduced blood products from two laboratories were analyzed. RESULTS:  At the level of 3.3 WBCs per µL, none of the laboratories met the requirements for all three blood products. The LeucoCOUNT method met requirements at more laboratories than the LeukoSure method for RBCs and PLTs, but the opposite was true for plasma. Routine QC data showed that >99 percent of the flow cytometric measurements for WBC‐reduced products was below the 95 percent prediction interval at 3.3 WBCs per µL. CONCLUSION:  None of the laboratories met the requirements for accuracy and precision for all three blood products. Nevertheless, routine results showed that in >99 percent of the products, WBC counts were below guideline limits. Therefore, both flow cytometric methods are suitable for QC with pass‐fail criterion.