Do I Need a Medical Expert to File a Malpractice Lawsuit in Illinois?

 Posted on October 29, 2026 in Medical Malpractice

Illinois requires an expert review when you file a medical malpractice lawsuit. Your attorney submits a sworn statement called an affidavit. A medical professional’s written report must explain why the claim has a valid basis. Exceptions apply when deadlines are near or records are missing. These requirements can take time to complete, so preparing early is important. If you are considering a claim in 2026, our Decatur, IL medical malpractice lawyers can review your case, arrange the necessary medical evaluation, and explain your options.

What Does Illinois Require Before Filing a Medical Malpractice Lawsuit?

The statute 735 ILCS 5/2-622 covers claims for injuries or death caused by medical, hospital, or other healthcare malpractice. Your attorney files an affidavit confirming that a qualified professional reviewed the case and found a reasonable basis for it. A written report explains the professional's reasons. The attorney also confirms that the review supports filing the lawsuit.

If there is more than one defendant, each one needs a separate certificate and report. However, one thorough review can sometimes address multiple defendants. A report that merely says malpractice occurred without explaining why is not enough.

Failing to file these is grounds for dismissal, but a judge can permit corrections in appropriate cases. A filing mistake does not always end the case permanently.

Who Can Review an Illinois Medical Malpractice Claim?

The statute sets specific qualifications rather than allowing any physician to sign off. The reviewer needs relevant knowledge and experience, including practice or teaching in the field within the last six years. The professional also needs qualifications related to the treatment being challenged.

For claims against most physicians, hospitals, and nurses, the written report generally comes from a physician licensed to practice medicine in all its branches. Claims against dentists, psychologists, podiatric physicians, and certain other professionals require a reviewer in the same profession and license class.

Choosing the right reviewer matters because a medical license alone does not establish expertise in every type of treatment. The filed report can omit the reviewer's identity, but anonymity is not guaranteed throughout litigation.

Can You File an Illinois Malpractice Lawsuit Without an Expert Report?

When the filing deadline would prevent an expert consultation, the plaintiff can submit an affidavit explaining why the report could not be obtained in time. The written report and certificate are then due within 90 days after filing the lawsuit.

Another exception addresses missing medical records. If a provider does not supply properly requested records within 60 days, the attorney can file the appropriate affidavit. The report then becomes due within 90 days after receiving those records.

These extensions require careful planning. Missing the follow-up deadline exposes the case to dismissal, even when the injury is serious. A judge can sometimes allow you to correct the paperwork, but that is not guaranteed.

Why Does Illinois Require an Expert Report for Medical Malpractice?

The purpose of an expert report is to filter out cases that lack medical support before a defendant has to answer them. The requirement does not mean a reviewer decides whether the patient will win. Instead, the report establishes a starting point for litigation. It does not replace the evidence needed to prove negligence.

Gathering records and obtaining an expert's written opinion takes time. A lawyer often starts by collecting:

• Hospital and doctor's office treatment records

• Imaging results, laboratory reports, and medication records

• Discharge instructions and follow-up treatment notes

• Medical bills and records of ongoing care

These documents help the reviewer understand what happened and whether the care met accepted medical standards. Missing records can delay the process.

A firm can decline a case when the available records do not support the required medical opinion. That decision does not necessarily mean the patient experienced no harm.

What Else Do You Need to Prove in an Illinois Medical Malpractice Case?

You must show what care the provider should have given and how they failed to meet that standard. You must also prove that this failure caused you harm. Expert testimony commonly helps explain these issues. Showing that a provider made an error is not enough without proving that the error caused an injury.

The two-year filing deadline usually starts when you knew or should have known that improper medical care could have caused your injury. There is also a four-year outside limit from the medical mistake. For minors, the general deadline is eight years from the act, but no later than their 22nd birthday. Certain exceptions apply.

Schedule a Free Consultation With Our Champaign, IL Medical Malpractice Attorneys

Our firm brings over 100 years of combined experience to these cases. Attorney Todd Bresney previously worked at the Federal Trade Commission and at the State’s Attorney’s Office for Cook County. If you are considering a medical malpractice claim in 2026, our team can help you understand the evidence and filing requirements.

Contact Kanoski Bresney at 888-826-8682 to talk to our Decatur, IL medical malpractice lawyers today.