Here the focus is on applications in the life sciences where the target population might be a disease registry (focus is on estimating the undercount of the registry) or a human population to be screened for disease (focus is on estimating the screened population with disease where the screening did not find disease). Current interest focuses on zero-truncated count data modelling (the unobserved zeros is the focus of interest) using regression modelling. Other approaches generalise the Lincoln-Petersen method and also sample size question are in the focus of research. Collaboration exists with a variety of academic partners (in the US, Italy, Turkey, the Netherlands and Germany) as well as institutions applying these ideas including the UK¡¯s Animal Health Veterinary Laboratory Agency.