Presents a hidden Markov model for automatic karyotyping. Previously, we demonstrated that this method is robust in the presence of different types of metaphase spreads, truncation of chromosomes and minor chromosome abnormalities, and that it gives results superior to neural networks on standard data sets. In this paper, we evaluate it on a data set consisting of a mix of chromosomes obtained from blood, amniotic fluid and bone marrow specimens. The method is shown to be robust on this mixed set of data, as well as giving far superior results than those obtained by neural networks.