How to Sue a Doctor for Misdiagnosis

If your doctor diagnosed you incorrectly or missed your condition altogether, a medical malpractice lawyer in Chicago can guide you through how to sue a doctor for misdiagnosis in Illinois. You might have sufficient grounds for a medical malpractice claim if you or a loved one has suffered harm due to a misdiagnosis. You will need to demonstrate that the doctor violated the accepted medical standard of care under the conditions for your claim to be successful. Simply put, a doctor with similar training within the same medical community under the same conditions would have diagnosed your health condition correctly.

Medical malpractice cases involving misdiagnosis usually have a higher burden of proof. A medical malpractice lawyer with demonstrated experience in resolving cases like yours can help you figure out how to sue a doctor for misdiagnosis. The lawyer can investigate your case and assemble the evidence needed to prove the doctor’s negligence and build a strong claim. 

What Is Misdiagnosis?

A misdiagnosis occurs when a doctor assesses a patient’s illness or health problem incorrectly. It can also happen when a doctor misinterprets a patient’s laboratory results. Missing a diagnosis also amounts to a misdiagnosis. A missed diagnosis happens when a healthcare provider gives a patient a clean bill of health, despite the patient having an underlying medical condition. 

Other issues that might qualify as a misdiagnosis include: 

  • Delayed Diagnosis: A doctor correctly diagnoses an illness or health problem after taking longer than necessary. 
  • Failure to notice complications: A doctor accurately diagnoses a medical condition, but fails to detect complications of that condition. 
  • Failure to detect a related medical condition: A doctor makes an accurate diagnosis of one medical condition, but does not diagnose another related condition. 
  • Failure to detect an unrelated medical condition: The doctor provides an accurate diagnosis of one medical condition, but does not diagnose an unrelated second medical condition. This diagnostic error happens when the doctor fails to perform a comprehensive diagnosis or bases the diagnosis of a serious medical condition on one basic diagnostic test. 

A misdiagnosis may exacerbate your medical condition. It may delay an accurate diagnosis of your condition. It may also lead to additional complications or even death when life-threatening diseases, like cancers, are involved. 

Common Examples of Misdiagnosis

Up to 20% of patients with serious health problems get misdiagnosed by their doctors. That is a significant number, considering a misdiagnosis is one of the most common and deadly types of medical malpractice. Although any medical condition can be misdiagnosed, some conditions tend to be misdiagnosed more frequently than others. Commonly misdiagnosed conditions include:


A cancer misdiagnosis often occurs when a doctor misreads symptoms or misinterprets test results. A cancer misdiagnosis can cause serious physical, mental, and financial implications. A victim of a wrong cancer diagnosis undergoes unnecessary treatment procedures, causing the victim to develop debilitating side effects. A delayed cancer diagnosis allows the disease to metastasize or spread throughout the body. 


Bronchiectasis and asthma often share similar symptomatic and physiological clinical manifestations. Doctors sometimes fail to diagnose these two conditions correctly. You might be diagnosed with bronchiectasis when you have asthma and vice versa.  


Rheumatoid arthritis and chronic fatigue syndrome share similar symptoms with lupus. Healthcare providers may confuse these two conditions for lupus. 

Heart Attack 

Healthcare providers may misdiagnose dyspepsia, inflammatory bowel disease (IBD), and panic attacks as heart attacks. 

Parkinson’s Disease                   

This disease mimics stroke or Alzheimer’s disease. For this reason, doctors may sometimes mistake Parkinson’s disease for any of the two diseases. 

 When Can You Sue a Doctor For a Medical Misdiagnosis in Illinois?

In Illinois, you have two years from when you recognized or should have recognized the injury caused by medical misdiagnosis to sue a doctor for damages. This window of time is called the statute of limitations.

The Illinois statute of limitations for medical malpractice is extended for injured victims who do not discover their injuries caused by medical misdiagnosis immediately. Such victims may bring a medical malpractice lawsuit within four years from the date of the misdiagnosis. 

Medical malpractice victims who were minors (under 18 years) at the time of the medical misdiagnosis also have a specific statute of limitations. Such victims must file their case within eight years from the date of the misdiagnosis, but not later than the victim’s twenty-second birthday. 

You may lose your right to pursue compensation from the negligent doctor if you miss the applicable filing deadline. So, it’s crucial to familiarize yourself with the specific filing deadline applicable to your case. 

Besides the specific filing deadline, there are stringent procedures to follow, investigations to conduct, and a higher burden of proof to satisfy. Involving a lawyer as early in the process as possible can improve your chances of proving a misdiagnosis claim and receiving reasonable compensation. 

 How to Prove a Misdiagnosis Claim

A successful misdiagnosis claim involves proving the following four elements: 

A Duty of Care 

You must demonstrate that the doctor owed you a duty of care to prove a misdiagnosis claim. Proving a duty of care involves showing that a doctor-patient relationship existed between you and the doctor. You can prove the existence of such a relationship by presenting medical records.

A Breach of the Duty of Care  

A misdiagnosis itself is not sufficient proof of negligence. Competent doctors can (and do) incorrectly assess medical conditions, even when exercising reasonable caution. You must demonstrate that a similarly-trained doctor would not have misdiagnosed your medical condition under the same conditions. 

A medical expert witness testimony will be necessary to explain the steps a similarly-trained doctor would have taken under the same conditions. The testimony will also show whether the defendant satisfied that standard of care. 

A Direct Causal Link Between the Harm and Breach of Duty of Care         

This element is the hardest to prove. The reason is that you were already ill or injured before you sought treatment from the doctor. You must provide sufficient evidence to show that the doctor’s negligence caused your injury or exacerbated your condition. A medical expert witness testimony will be necessary to establish a direct causal link between your injury and the doctor’s negligence. 

Actual Damages 

You must demonstrate that you suffered compensable damages due to the misdiagnosis to win a medical malpractice case. Simply put, you incurred expenses and losses due to your injury. You cannot sue a doctor for misdiagnosis if you did not suffer any harm. 

Example 1

Let’s assume a doctor diagnosed you with bronchiectasis when you had asthma. The doctor prescribed a medication that was effective against asthma. In this scenario, you did not suffer any harm from the misdiagnosis. 

Example 2

Let’s assume a doctor diagnosed you with inflammatory bowel disease (IBD) when you had colorectal cancer. The doctor then prescribed medications that did not help your condition. Your colorectal cancer developed further, requiring costly and aggressive treatment procedures when a correct diagnosis was made. In this scenario, the misdiagnosis caused you to suffer physically, emotionally, and financially. 

Damages Available in Misdiagnosis Cases 

Recoverable damages in misdiagnosis cases fall into two categories: compensatory damages and exemplary damages. Compensatory damages seek to compensate you for the actual harm and losses suffered. They consist of economic damages and non-economic damages. 

Economic damages describe objective, quantifiable financial losses. They include medical expenses (past, present, and future), lost wages, and lost or reduced earning capacity. Non-economic damages describe subjective, non-financial losses that are not easily quantifiable. They include pain and suffering, emotional trauma, disfigurement, disability, loss of companionship or consortium, and loss of ability to enjoy life. 

You may receive exemplary damages, also called punitive damages, in Illinois if the presented evidence shows that the doctor acted deliberately, maliciously, dishonestly, or with a deliberate lack of concern for possible consequences. These damages seek to punish the doctor for the outrageous behavior and discourage similar wrongdoing in the future. 

How a Medical Malpractice Lawyer Can Help You 

Obtain an Affidavit of Merit 

In Illinois, you must accompany your lawsuit with a document indicating that you have consulted a medical professional. This document is called an affidavit of merit. It must show that you have (or had) a medical condition, another medical professional would have accurately diagnosed your illness, and you have grounds for a medical malpractice lawsuit. 

If you cannot file the affidavit of merit together with the lawsuit, you must file it within 90 days from when you filed the lawsuit. The document must comply with the state requirements. A lawyer with a long history of successfully handling misdiagnosis cases has established professional connections with many healthcare providers. The lawyer can help you identify a healthcare provider to corroborate your medical condition and prepare a compliant affidavit of merit. 

Assemble Additional Information to Prove Your Misdiagnosis Case 

Your lawyer can investigate your misdiagnosis case to obtain additional evidence to strengthen your compensation claim. Some of the documents and information the lawyer might obtain include: 

Medical Records 

Your lawyer can advise you to seek a second or even third opinion from a different medical professional. If the second and third opinions disagree with the first opinion, it might indicate that your first doctor misdiagnosed your condition. In fact, a different second opinion is one of the most common signs of medical malpractice

Your lawyer can obtain your medical records, including test results, imaging reports, prescription records, and doctor’s notes. These documents can help prove that you had a medical condition and were misdiagnosed. 

Medical Expense Receipts and Employment Records

Your lawyer will review your medical bills, invoices, and receipts to calculate your past and current medical expenses. The lawyer will also estimate your future medical costs using those documents. Your employment records, including pre-injury pay stubs, tax returns, and a letter from your employer, will help determine and prove your lost wages. 

Testimony from Medical Professionals 

Your lawyer can consult with medical professionals to determine the impact of the misdiagnosis on the quality of your life. The lawyer will work with medical professionals in the relevant field. If you were diagnosed with IBD instead of colorectal cancer, for instance, your lawyer will consult another oncologist regarding your condition. 

Determine the Liable Party in Your Case 

The liable party could be someone else other than your doctor. It could be a lab technician who failed to analyze test results correctly or a medical equipment manufacturer whose medical equipment produced unreliable results. It could also be a hospital that did not maintain its medical equipment properly. 

Your lawyer can analyze facts in your medical records and other documentation to identify the liable party. The lawyer can initiate multiple claims to pursue damage if available evidence shows that several parties breached their duty of care to provide you with an accurate diagnosis and appropriate treatment. 

Handle All Communications and Settlement Negotiations  

An insurance adjuster might contact you soon after initiating your lawsuit. This adjuster might act friendly and promise to help you, but the adjuster does not have your best interests at heart. Avoid recording a statement or answering questions that might disprove your injuries. Instead, politely ask the adjuster to direct all the questions about your case to your lawyer. 

Insurance adjusters often search for information to reduce your settlement amount or deny your claim altogether. Your lawyer will advise you on what to do (and what not to do) when an adjuster or representative of the liable insurer approaches you. 

During settlement negotiations, your lawyer will present enough evidence to prove the injuries and losses you have suffered due to the misdiagnosis. The lawyer will fight for a compensation amount that can fully pay for the damages arising from your injury or medical condition.  

File a Lawsuit 

Your lawyer will go to court if the doctor or doctor’s insurer denies liability or fails to provide a fair settlement offer. A lawyer who has argued many medical malpractice cases before a jury, judge, or both will know the type of evidence required to satisfy the burden of proof. Having a lawyer on your side increases the odds of a successful outcome at trial.

Chicago personal injury and workers’ compensation attorney Howard Ankin has a passion for justice and a relentless commitment to defending injured victims throughout the Chicagoland area. With decades of experience achieving justice on behalf of the people of Chicago, Howard has earned a reputation as a proven leader in and out of the courtroom. Respected by peers and clients alike, Howard’s multifaceted approach to the law and empathetic nature have secured him a spot as an influential figure in the Illinois legal system.

Years of Experience: More than 30 years
Illinois Registration Status: Active
Bar & Court Admissions: Illinois State Bar Association, U.S. District Court, Northern District of Illinois, U.S. District Court, Central District of Illinois
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