Abstract: A process for quantification of cell populations or subpopulations, by incubating a sample with labelled antibodies directed against characteristic surface antigens of the cell population to be quantified to form labelled antibody/antigen complexes. Standards with known, differing particle concentration and having comparable sedimentation behavior to the cells to be determined and further, carrying molecules which are directed against the labelled antibody or a part hereof are also incubated with the labelled antibodies. The cells of the sample solution, as well as the particles of the standard solution, are separated off from the excess labelled antibodies and the amount of the labelling is measured not only on the cells but also on the particles. By comparison of the measurement value from the sample with the measurement values from the standard solutions, there is ascertained the number of cells to be determined in the sample.