Automated counting of human tumour colonies in the Courtenay-Mills assay system.

A procedure for using the Omnicon automated image analysis system for counting colonies grown from a human tumour cell line (COLO 205) in the Courtenay-Mills assay is described. This involves the transfer of the agar medium from culture tubes into petri dishes. Comparisons of observer and instrument counts were done on a blinded basis. Run-to-run correlation coefficient was 0.996 for automated counting and the inter-observer correlation coefficient was 0.984. Both assessments showed a linear relationship between the number of cells plated and the number of colonies grown. Automated colony counting is fast, reliable and provides additional information on colony size distribution, not obtainable with manual counting. This automated procedure will greatly facilitate in vitro drug sensitivity evaluation.