What Is Diagnostic Medical Malpractice?

Diagnostic medical malpractice refers to situations in which a healthcare provider fails to accurately or promptly identify a patient’s medical condition, resulting in harm that could have been prevented with proper diagnosis and timely treatment. This form of negligence disrupts the critical early stages of care—when accurate diagnosis can make the difference between recovery and irreversible harm.

The term includes a range of errors, such as misdiagnosing one condition for another, failing to order necessary tests, or ignoring warning signs in lab results. Diagnostic malpractice doesn’t necessarily require a complete failure to identify the illness—it also includes delays or partial diagnoses that lead to complications, suffering, or wrongful death.

For example, a provider who misreads a mammogram and misses early signs of breast cancer could be liable if the patient later develops an advanced form of the disease that could have been prevented with early intervention. Similarly, if a stroke victim is dismissed from the emergency room without adequate testing and later suffers permanent damage, that too may constitute diagnostic malpractice.

Diagnostic medical malpractice occurs when a healthcare provider fails to correctly diagnose a patient’s condition in a timely manner, resulting in harm that could have been prevented. In Illinois, this is one of the most common and serious forms of medical negligence—and often one of the most difficult to detect until it's too late.

Types of Diagnostic Errors

Diagnostic malpractice can take several forms:

• Misdiagnosis: Diagnosing a patient with the wrong condition (e.g., mistaking a heart attack for acid reflux).

• Delayed Diagnosis: Failing to diagnose a condition until it has progressed significantly, such as cancer that spreads because of delayed detection.

• Failure to Diagnose: Completely overlooking a medical issue despite clear symptoms or test results.

• Failure to Act on Test Results: Ignoring or misinterpreting lab tests, imaging scans, or biopsy reports.

• Failure to Refer: Not sending a patient to a specialist when the condition is outside the provider’s scope.

Why Diagnostic Malpractice Happens

Common causes include:

• Incomplete patient history or examination

• Misreading X-rays, MRIs, or lab results

• Poor communication among medical teams

• Overworked or undertrained staff

• Systemic issues in hospital or clinic workflows

Consequences of Diagnostic Malpractice

A delayed or incorrect diagnosis can lead to:

• Worsening of the original illness

• Unnecessary treatments or surgeries

• Missed opportunity for life-saving interventions

• Permanent disability

• Emotional trauma and financial loss

Real-World Examples of Diagnostic Malpractice

• Missed Stroke in the ER: A 52-year-old man arrived at a Chicago emergency room complaining of numbness and slurred speech. He was diagnosed with dehydration and sent home. Hours later, he suffered a major stroke that left him permanently disabled. Timely imaging would have revealed the early signs of a stroke.

• Delayed Cancer Diagnosis: A woman in the suburbs of Chicago repeatedly visited her primary care provider for persistent fatigue and weight loss. Blood tests were ordered but never followed up. Months later, she was diagnosed with late-stage lymphoma—too advanced for curative treatment.

• Misdiagnosed Heart Attack: A young father with chest pain was told he had acid reflux and was given antacids. In reality, he was having a heart attack. The delay in treatment caused severe cardiac damage requiring lifelong care.

These cases illustrate the devastating impact diagnostic errors can have on patients and their families—and the importance of pursuing legal accountability when negligence occurs.

A delayed or incorrect diagnosis can lead to:

• Worsening of the original illness

• Unnecessary treatments or surgeries

• Missed opportunity for life-saving interventions

• Permanent disability

• Emotional trauma and financial loss

How to Prove a Diagnostic Malpractice Case in Illinois

To bring a successful claim, your legal team must show:

1. A provider-patient relationship existed.

2. The provider breached the standard of care—what a competent doctor would have done in the same situation.

3. The breach directly caused harm—for example, a delay in diagnosing a stroke led to irreversible brain damage.

4. You experienced measurable damages, such as medical expenses, lost wages, or pain and suffering.

In Illinois, a medical expert is usually required to confirm that a diagnostic error occurred and caused harm.

How Long Do I Have to File a Diagnostic Malpractice Lawsuit?

Under Illinois law (735 ILCS 5/13-212):

• You generally have 2 years from when you discovered (or should have discovered) the harm.

• A lawsuit must be filed no more than 4 years from the date the mistake occurred.

• For minors, the time limit extends until their 22nd birthday.

Why Work With a Diagnostic Malpractice Attorney in Chicago?

Proving a diagnostic error isn’t easy. At Hurley McKenna & Mertz, P.C., we have decades of experience handling complex malpractice claims involving:

• Missed cancer diagnoses

• Heart attack and stroke misdiagnoses

• Emergency room diagnostic errors

• Infections and post-surgical complications

We work with leading medical experts and investigators to uncover the truth and fight for maximum compensation.

Talk to a Diagnostic Malpractice Lawyer Today

If you believe a doctor failed to properly diagnose your condition—or delayed a diagnosis that worsened your health—contact Hurley McKenna & Mertz, P.C. for a free consultation. We represent clients across Chicago and throughout Illinois.

Serving clients in Cook County, DuPage County, Lake County, and beyond.