I work for a hospitalist group. I have learned that you list as many diagnosis codes as needed when billing. So if the hospitalist documents 1 diagnosis, I would list that. If he/she addresses 10, even though it's many, I will list all of those (unless a specialist is also using that dx code for the same DOS). Now, if one of the notes has 20 diagnosis, I don't list all 20, but I try to capture as much as I can. I was told that MCR and most commercial insurances only need 1-4 diagnosis codes. I am doing some research, but does anyone know if that's the case?