I think it depends on the employer and the work that they are doing. RADV audits are being performed on 2012 dates of service, so a company hired to perform this service for a health plan would need coders proficient in ICD 9. Presumably there will be audits on additional dates prior to ICD 10 implementation. In our company, we have auditors who work with both ICD 9 and 10, and we have coding specialists who are working on current data and primarily use ICD 10.