Question: My physician performs annual well visits for the employees of a company at the work site. I assumed place of service (POS) code 18 (Place of employment, worksite…) would be sufficient, but it said to use no later than May 1, 2013. Is this POS code still billable? If not, would the proper POS be 99 (Other place of service)? California Subscriber Answer: This answer hinges on how you are billing the services. Medical necessity is the overarching criteria for billing a third-party payer. If your physician goes on-site to perform annual well visits that the business requires of its employees, then the business is paying for the exams, not the insurance company. You would not bill your physician’s services to the insurance company for an E/M service or an annual wellness service that an employer requires. Thus, you would want to check with the employer to see how they want to see the service billed directly to them. POS may not matter if you are not billing these well visits to an insurance company, however.