Since 1979, medicine has been using a system of diagnostic coding called ICD 9. All medical diseases and conditions were assigned an alpha numeric code which had to be used for insurance pre-certifications, claims, payments, etc.
Previously there were 13,000 codes of 4 or 5 digits. Starting in October 2015, the government has mandated that we start using ICD 10, a system of approximately 70,000 codes with up to 7 digits. This vastly more complex system defines disease more specifically and more rigidly than the previous version. During the switch, please be patient. The system is much more complicated and no doubt there will be issues.