A timely and accurate diagnosis is often the first and most critical step in effective medical treatment. When a doctor fails to correctly identify a condition — or delays diagnosing it — the consequences can be severe or even life-threatening. If you’ve suffered harm due to misdiagnosis Illinois patients unfortunately experience, you may have a medical malpractice claim under state law.
Misdiagnosis and delayed diagnosis cases are complex. They require proof that a healthcare provider failed to follow the accepted diagnostic standard of care and that this failure caused measurable harm.
Below is a detailed explanation of how Illinois law applies to diagnostic malpractice claims.
What Is Misdiagnosis or Delayed Diagnosis?
Missed Diagnosis
A missed diagnosis occurs when a physician fails to identify a condition that is present, resulting in no treatment being provided.
Wrong Diagnosis
A wrong diagnosis occurs when a physician identifies a condition incorrectly, leading to inappropriate treatment while the actual condition goes untreated.
Delayed Diagnosis
A delayed diagnosis occurs when a physician eventually identifies the correct condition but takes unreasonably long to do so, allowing the condition to worsen.
For a general overview of medical malpractice claims, visit:
Medical Malpractice Attorney.
Commonly Misdiagnosed Conditions
Cancer
Failure to detect cancer early can significantly reduce treatment options and survival rates.
Heart Attack
Heart attacks are sometimes misdiagnosed as indigestion or anxiety, particularly in women.
Stroke
Delayed recognition of stroke symptoms can result in permanent brain damage.
Infections and Sepsis
Failure to diagnose infections promptly may lead to sepsis and organ failure.
Appendicitis
Missed appendicitis can result in rupture and life-threatening complications.
How Diagnostic Errors Occur
Diagnostic errors may result from:
- Failure to order appropriate tests
- Misreading laboratory results or imaging
- Failure to follow up on abnormal findings
- Ignoring patient complaints or symptoms
- Inadequate medical history review
- Poor communication between providers
The Differential Diagnosis Standard
Physicians are expected to use a “differential diagnosis” approach — systematically ruling out potential causes of symptoms through appropriate testing and evaluation. Failure to conduct an adequate differential diagnosis may constitute malpractice.
Proving Diagnostic Malpractice in Illinois
Duty
A doctor-patient relationship must exist.
Breach
The provider must have failed to meet the diagnostic standard of care.
Causation
The delay or misdiagnosis must have directly caused harm or worsened the patient’s condition.
Damages
The patient must have suffered measurable injury.
For more information about the legal elements of a malpractice claim, visit:
Proving Medical Malpractice in Illinois.
Certificate of Merit Requirement (735 ILCS 5/2-622)
Illinois law requires plaintiffs in medical malpractice cases to file a certificate of merit under 735 ILCS 5/2-622.
This means a qualified healthcare professional must review the case and provide a written report confirming that a reasonable basis exists for the claim before a lawsuit can be filed.
Statute of Limitations and Repose (735 ILCS 5/13-212)
Two-Year Discovery Rule
Under 735 ILCS 5/13-212, most medical malpractice claims must be filed within two years from the date the patient knew or reasonably should have known of the injury.
Four-Year Statute of Repose
In general, no malpractice action may be filed more than four years after the date of the alleged negligent act, regardless of when it was discovered, subject to limited exceptions.
These deadlines are strict and can bar claims if not followed carefully.
The Role of Expert Testimony
Expert testimony is essential in misdiagnosis cases. A qualified medical expert must explain:
- What the proper diagnostic process should have been
- How the provider deviated from the standard of care
- How the error caused harm
Damages Available in Misdiagnosis Cases
Victims of misdiagnosis Illinois law recognizes may recover:
- Medical expenses (past and future)
- Lost wages
- Loss of earning capacity
- Pain and suffering
- Disfigurement
- Loss of normal life
Illinois does not impose a statutory cap on most medical malpractice damages.
Related: Surgical Errors
Diagnostic errors may lead to unnecessary or harmful surgical interventions.
For more information, see:
Surgical Errors and Medical Malpractice in Illinois.
Frequently Asked Questions
Is a wrong diagnosis always malpractice?
Not always. Malpractice requires proof that the provider deviated from the accepted standard of care, not merely that the diagnosis was incorrect.
How do I prove that a delayed diagnosis caused my injury?
Expert testimony is typically required to show that earlier diagnosis would have changed the outcome.
What is a certificate of merit?
It is a written statement from a qualified healthcare professional confirming that the claim has a reasonable basis.
How long do I have to file a misdiagnosis claim?
Generally two years from discovery of the injury, but no more than four years from the negligent act, subject to limited exceptions.
Contact Parker & Parker Attorneys at Law
Diagnostic errors can change lives. If you believe you have been harmed due to misdiagnosis Illinois law may provide a path to compensation.
Parker & Parker Attorneys at Law represents patients and families throughout Peoria and Central Illinois in medical malpractice claims.
Learn more on our Medical Malpractice Attorney page.
Parker & Parker Attorneys at Law
300 NE Perry Ave
Peoria, IL 61603
Phone: 309-673-0069
Contact us today to discuss your case.