Method for obtaining informative cells

A method for processing a liquid sample of uncultured cells for in situ hybridization analysis, wherein the sample cells that are informative are separated from the sample cells that are non-informative, comprising the steps of:

• a) incubating liquid sample with phenylmethylsulfonylfluoride (PMSF);
• b) transferring the liquid sample of step a) containing both uncultured informative cells and non-informative cells onto a solid substrate wherein the surface tension of the liquid sample is sufficient to maintain the liquid sample beaded on the surface of the solid substrate;
• c) incubating the beaded liquid sample on the surface of the solid substrate for a period of time in the range of about 15 minutes to about 30 minutes for the selective settling of informative cells onto the surface of the solid substrate;
• and
• d) breaking the surface tension of the liquid sample wherein the liquid portion of he sample is removed along with the non-informative cells and wherein the informative cells remain on the surface of the solid substrate.

A kit for preparing cells for in situ hybridization analysis, comprising:

• a) a container for holding the components;
• b) a solid substrate;
• c) a protease inhibitor comprising phenylmethylsulfonylfluoride (PMSF)
• d) a short chain fatty acid selected from the group consisting of sodium butyrate, sodium propionate and sodium valerate;
• e ) a fixative;
• and
• f) a nucleic acid probe (s).