particle classification

The CytoClus data analysis program offers options to draw boxes or polygons around these clusters in these dotplots to make a specific selection set for a target cluster. Such a selection set is a collection of boundaries on the measured parameters, which means that it is a morphological description. The discrimination power is increased if a cluster is selected in more dotplots. Statistics for this and every other distinguishable group can be generated (number of counts, averages and standard deviations etc.). The number of cells counted in these selection sets is automatically converted to a cell concentration basing on the measured amount of sample volume analyzed. If a one or more of such selection sets are defined, CytoClus can be used to automatically calculate the contents of these sets for a series of sample files in a particular directory. In this manner an overview of cell concentrations and/or other properties can be obtained for a number of sample files as measured in a certain experiment or monitoring interval.

The next step is to assign names of species to these selected groups (selection sets): there is a cluster here, but what is it ? The microscope is generally of invaluable help to construct the libraries. with the most effective method being to grow cultures and base selection sets on results from measuring these cultures. Field samples rarely contain over 50 species however, and often many of these can be discriminated on the basis of the scan shapes (silico-images) and the relative numbers (particles per ml). Existing (libraries of) already labelled selection sets may give a good fit when representative for the location and the season. A direct way is to image the individuals of a target group by "imaging-in-flow" or by physical sorting. CytoSense instruments can be upgraded with imaging-in-flow or sorting capabilities. Without such upgraded instruments, calibration can be done well by microscopical analysis of one or a few samples in a series.