A blood processing chamber (22) separates blood into constituents including a plasma constituent that includes a platelet volume An optical monitor (98) detects the optical density of the plasma constituent and generates a first output indicative of the optical density A processing element (100) integrates the first output relative to the volume of plasma constituent and generates an integrated output The integrated output correlates to the platelet volume A second processing element (72) generates a third output based, at least in part, upon the integrated output, which encompasses parameters for storing the platelet volume

Blood processing systems and methods which optically derive the volume of platelets contained in a plasma constituent

Platelet surface P-selectin measurements in platelet preparations: An international collaborative study

A multicenter study evaluating three methods for counting residual WBCs in WBC-reduced blood components: Nageotte hemocytometry, flow cytometry, and microfluorometry.

A viewing head (70) in a blood separation chamber (22) region monitors for the presence of an interface region between plasma and cellular blood components in the chamber (22). Sensed optical density values obtained by the viewing head (70) are compared to a calibrated threshold value by comparator (90) to generate a time pulse output. Calibration modules (94 and 96) derive the calibrated threshold value based upon either (i) a comparison of a sensed reference optical density value in the viewing head (70) to an expected optical density value for the reference material, or (ii) a sensed optical density value of plasma exiting the blood separation chamber (22), or both.

Interface detection and control systems and methods

The effect of leukocyte-reduction method on the amount of human cytomegalovirus in blood products: a comparison of apheresis and filtration methods.

BACKGROUND The increased demand for leukocyte-reduced platelet products has prompted actions both by blood suppliers and device manufacturers to develop effective quality assurance methods and improved devices for leukocyte-reduced platelet preparation. White cell (WBC) counting methods capable of counting WBCs substantially below 1,000 WBC/mL enhance these activities. The purpose of this study was to enhance and validate a method capable of counting 5-10 WBC/mL in platelets. METHODS We added marker chicken red blood cells (cRBC) at a known concentration to an aliquot of platelet concentrate containing propidium iodide stain solution (PI). A modified BD FACScan was used to analyze this mixture. The ratio of cRBC and WBC events observed was used with the cRBC concentration to calculate the WBC concentration. Validation was performed by analyzing standard curves prepared with leukocyte-depleted platelet diluent. Methods of preparing leukocyte-reduced platelets by apheresis and filtration were evaluated using this method. RESULTS The method was linear from 5,000 WBC/mL to 10 WBC/mL (r2 = 0.983). Residual WBCs in the platelet diluent hampered validation below 10 WBC/mL. Repeatability (CV) was 44% at 8 WBC/mL and 6.5% at 1,000 WBC/mL. The FACScan required frequent mixing of the sample and flushing with cleaning agents during acquisition. CONCLUSIONS This method has good linearity and reproducibility from 10-5,000 WBC/mL for platelets. It is suited for research and development work, and may be a useful adjunct method for quality assurance in the blood center.

L.J. Dumont

Papers

Enhanced flow cytometric method for counting very low numbers of white cells in platelet products