A multiwell cell settling and adherence chamber for morphology and differential counting

A simple multiwell chamber is described that can be used to prepare randomly distributed cells on a microscope slide, suitable for morphological identification and differential counting. To the eight wells of the chamber are added 50-μl volumes of cell suspension at concentrations of 10³-10⁶ cells/ml. As the cells settle, fluid is slowly wicked away by a damp filter paper sandwiched between the microscope slide and the acrylic top plate of the multiwell chamber. Within 20-40 minutes, the cell monolayers on the slide are completely dry. The combined settling and bulk fluid removal results in a distribution of adherent cells that are sufficiently spread to exhibit excellent morphology after staining. If the chamber is centrifuged for 30 seconds at 50x g immediately after addition of cells, recovery of cells in the monolayer is virtually 100%, and as few as 50 input cells per 50 μl can be detected. Agreement between predicted and observed differential counts of cell mixtures indicates that cells in the monolayer were distributed randomly.