An incident in medical malpractice can happen at any time. As a patient or loved one of a patient, it is important to understand how to prove it happened in a court of law. Jeff breaks it down for you, here! Q: How can a patient prove that medical malpractice took place in order to have a case? A: The only way a patient can prove that medical malpractice took place is by using a physician. In Ohio you must have a doctor testify. The attorney has to go out and first get an affidavit of merit before you file suit. That means the doctor looked at it and believes there’s a case. Then you get a specialist in the field and have that specialist look at the case at which point he or she can come in and write a report and testify both in deposition, which is before the actual trial, and of course at trial if the case is not settled.