There are many many different medical products and services. As of 2010, there were over 25,000 different codes in the ICD-10. The ICD-9 is a huge book filled with all of the medical orders that can be billed.
These codes are also getting updated pretty frequently, but in 2013, there was a huge addition to the new medical coding and billing codes, which updated it to the ICD-10. There are now six times as many codes as there were before.