This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Abstract Flow cytometry is now a standard analysis platform for diagnostic analysis of human blood samples, primarily through the use of immunophenotyping via cell surface marker labeling with fluorescently-tagged antibodies. Relevance of these applications covers a wide range of areas including leukemia/lymphoma diagnosis and patient specific management, infectious disease, transplant medicine (stem cell enumeration/ characterization), paroxysmal nocturnal hemoglobinuria (PNH) diagnosis and fetal hemoglobin detection. Although such analysis is routine, there are still problems that are amenable to improve flow instrumentation. In this collaboration with Dr. Charles Goolsby's clinical immunophenotyping laboratory, we will use the unique instrumentation developed in Projects 1 and 3 to directly address two of these problems: separation of overlapping fluorophores in multi-color flow analysis which are now routinely six-eight color and loss of subsets of white cells during red cell lysis procedures. The improved spectral resolution instrument developed in Project 3 will be used to determine if deconvolution of complete emission spectra from multiply-stained cells can improve the resolution and quantitation of different cell types as compared to the standard use of optical filters and a complex compensation matrix. The in-line sample preparation device developed in Project 1 will be used to determine if acoustic field separation of red and white cells in a flowing sample stream can eliminate the need for a red cell lysis step with its resultant loss of certain subsets of white cells, particularly fragile abnormal cells. The availability of several types of clinical samples through this collaboration will directly test the utility of these two instruments to address limitations of conventional flow cytometry in a real-world situation.