A Form 18 is the form you use to formally open a file at the Industrial Commission. Just because your employer or the adjuster is sending you to a doctor doesn’t mean they’ve accepted the claim. And it doesn’t mean you have a claim on file with the Industrial Commission. More often than you’d think an injured worker reports his claim to his employer, gets some medical treatment, and returns to work. After a while the injury is acting up and bothering him but when he tries to go back to the doctor his adjuster denies the claim saying that a Form 18 was not timely filed with the Industrial Commission. The fact that everyone “knew” about the claim doesn’t always make a difference. The Industrial Commission needs that Form 18. This is the only irrefutable way to have a claim established.