." >> reporter: the change says accretive's duane lisowksi will expand the number of diagnostic codes in this book from 13,000 to nearly 70,000. >> for example, the initial code here is accident. an accident may be animal ridden, it could be from a balloon... roller coaster, so you have all of these codes, but then if you think about taking each one of these and then building it out, being even more specific, a roller coaster with an animal... ( laughs ). exactly, you know? >> reporter: david dranove, a health management professor at northwestern university's kellogg school of management, says the new codes could mean big bucks for hospitals. >> sometimes you can make a lot more money by doing one procedure versus another, but to justify those procedures you have to have the right set of diagnostic codes. >> reporter: when accretive moved onto this vacant floor of chicago's bank america building a little over a year ago, it had no coders, billers or follow-up personnel. today, this space is filled with 140 of those employees and accretive plans to hire another 100 coders by the end of