A rapid and reproducible method for the separation of cells from radioactive media.

A simple method is described for the rapid separation of cells, containing radioactive material, from their suspending medium. Cells, in aqueous medium, are layered on fetal bovine serum in microfuge tubes. The tubes are immediately spun for 1 min, frozen in ethanol-dry-ice, and their tips sliced and assayed. This method is both faster and more convenient than currently employed techniques.