Though workers' comp laws differ by state, most jurisdictions require a injured or sick worker to notify their employer of an injury within 30 to 45 days of an accident or injury becoming known (failure to do so can potentially result in a denial of benefits).
Providing notification to an employer of a workers compensation compensable injury is typically done by giving notice to someone in a managerial position. However, in cases where a worker is unable to provide such notification (perhaps due to hospitalization), the requirement of formal notice is generally excused if the employer learns of, or should have known of, the worker's injury.
Once notification has been made to the employer, the employer should submit a report to the state worker's compensation board (or industrial commission) and notify the workers' comp insurance carrier. At that point, the workers' comp carrier will be in the position to begin paying an injured or sick worker's medical bills, as well as a percentage of the worker's average weekly income (usually 66 percent), though payment of temporary disability checks.
Sometimes the process happens differently. A worker may go see the doctor, and when the doctor discovers the injury or illness is work related, the doctor may ask the worker to fill out a workers' comp claim form, which will advise the employer and its insurance company that the worker has suffered a workplace illness or injury. In this case, when you return to work after seeing the doctor, it's still a good idea to tell your supervisor what happened.
A workers' compensation carrier can also reject your worker's claim. You can always appeal the rejection of a claim with the state workers' compensation board or industrial commission. In such cases, you'd be wise to seek the assistance of an attorney who specializes in workers' compensation claims.