CELL SUBSET (CS) PARAMETER TO RECORD THE IDENTITIES OF INDIVIDUAL CELLS IN FLOW CYTOMETRIC DATA

The Flow Cytometry Standard (FCS) for cytometric data (Dean et al.: Cy tometry 11:323-332, 1990) provides for appending an ANALYSIS section t o a data file, but it does not explicitly provide for recording the id entities of individual cells. We propose an extension to the FCS defin ition in order to record the identity of each individual cell in list mode data. In order to do so, one first defines the subpopulations of cells to be identified and one then assigns a number to each defined p opulation. For example, in an analysis in which peripheral blood monon uclear cells are labeled with antibodies to CD3, CD4, and CD8, the ''n egative'' lymphocytes that are labeled with none of the antibodies cou ld be identified as population 1, the CD3(-)CD4(-)CD8(+) lymphocytes a s population 2, etc. As the measured values from each cell are analyze d, the number that identifies the population to which that cell belong s is assigned as the value of an additional parameter. Since this proc edure merely adds a new parameter, the only necessary extension to the FCS specification is that a particular name is recognized for this pa rameter. We propose that CS (abbreviation for cell subset) be recogniz ed as the name acid that CS be used as the value for the $PnN (paramet er name) keyword in the FCS file TEXT. The CS values that are created can be used to aid in data analysis and can be permanently recorded in a conventional FCS file. A data file that is saved with CS values inc ludes an explicit and integral record of the complete analysis, regard less of the complexity of the analysis. We describe how to create and record the CS parameter, provide examples of how the CS parameter can be used to assist in data analysis, and propose ways in which the CS p arameter can be used to monitor quality control. (C) 1994 Wiley-Liss, Inc.