Wrong Diagnosis, Real Surgery: How a Biopsy Mix-Up Becomes a Malpractice Claim

Nobody forgets the moment they’re told they have cancer. The phone call, the quiet room, the doctor choosing words carefully. Most people remember exactly where they were standing. You meet with a surgeon, schedule the operation, and brace for treatment. But imagine, months later, it’s discovered that the cancer cells on your biopsy came from someone else. Not a close call or a difficult judgment, but a stranger’s cancer, mistakenly placed on your biopsy slide.

It sounds unlikely, but laboratory errors happen when policies and procedures are not in place or are not enforced. During processing, a tiny fragment of tissue from one patient’s biopsy can end up on another patient’s slide. Lab professionals call some of these stray fragments “floaters.” If the pathologist doesn’t catch one, a healthy patient can receive a false-positive cancer diagnosis and go through surgery, chemotherapy, or radiation they never needed, often with devastating consequences for the patient’s overall physical and mental health.

If lab contamination happened to you or someone you love, it may not have been bad luck. Laboratories are required to have safeguards against contamination and mix-ups, and when they fail, the law may hold them responsible. Below, we explain how these errors happen, how they’re discovered, and when they may amount to laboratory contamination malpractice, which typically falls under medical malpractice lawsuits.

What Is Laboratory Specimen Contamination?

Laboratory specimen contamination occurs when foreign material is introduced into a patient's specimen or slide during collection, handling, processing, or testing. In pathology laboratories, this can occur when a small fragment of tissue from one patient’s biopsy mistakenly ends up on another patient’s microscope slide, or becomes enmeshed with the other patient’s tissue sample. These foreign tissue fragments are sometimes referred to as “floaters.”

Consider a patient who undergoes a biopsy to determine whether a suspicious growth is cancerous. The patient's actual tissue is benign, meaning it does not contain cancer. However, during laboratory processing, a small fragment of cancerous tissue from another patient mistakenly becomes attached to the slide, unbeknownst to lab personnel or the pathologist.  

When the pathologist examines the slide, those cancerous cells may be mistaken for part of the patient's own tissue, resulting in an incorrect cancer diagnosis. If the contamination goes undetected, the patient may undergo unnecessary surgery, chemotherapy, radiation, or other life-altering treatment for a disease they never had.

How Does a Biopsy Mix-Up or Lab Contamination Occur?

Most patients are unaware of the number of steps involved in processing a biopsy. After tissue is removed from the body, it typically passes through the hands of several healthcare professionals and undergoes multiple preparation procedures before a pathologist examines it under a microscope.  

The process generally involves:

1. Collection and labeling: A physician obtains suspicious tissue during a biopsy or surgical procedure. The specimen is placed in a container, usually with a preservative, and labeled with the patient's identifying information.

2. Laboratory intake (accessioning) and grossing: The specimen is received by the laboratory, assigned an identification number, and examined by a pathologist, pathologists' assistant, or other laboratory staff. Portions of the tissue are selected for further testing and placed into small containers called cassettes. This step is known as grossing.

3. Tissue processing and preparation: Laboratory personnel process the tissue using various chemicals before embedding it in paraffin wax. A histotechnologist or histotechnician then uses a specialized instrument called a microtome to cut extremely thin sections of tissue. These sections are commonly placed in a warm water bath to flatten them before being transferred onto glass microscope slides.

4. Staining and interpretation: The slides undergo staining procedures to make the cells easier to examine. A pathologist then reviews the slides under a microscope and issues a report identifying the findings.

Each step can present opportunities for contamination or other errors when reasonable care is not taken. Laboratories are expected and required to have procedures and safeguards in place to prevent contamination, specimen mix-ups, and other errors. When those procedures are inadequate or not followed, patients can suffer serious consequences and catastrophic damages.

When Does Laboratory Contamination Constitute Medical Malpractice?

To establish a viable laboratory contamination malpractice claim, it is generally necessary to show that a healthcare provider or laboratory failed to meet the applicable standard of care and that the failure caused injury. 

Certain mistakes in the handling, processing, or interpretation of tissue specimens may constitute negligence. Examples include:

• Inadequate cleaning, or no cleaning at all, of instruments, equipment, or workstations between specimens, allowing tissue fragments from one patient to contaminate another patient's sample.

• Failure to properly clean or maintain water baths, cutting equipment, or staining solutions used during slide preparation.

• Processing similar tissue specimens back-to-back without appropriate safeguards, increasing the risk that contamination or specimen mix-ups will go undetected.

• Mislabeling specimens, tissue blocks, or slides, or failing to properly verify patient identifiers throughout the laboratory process.

• Handling multiple open specimens simultaneously without appropriate precautions, increasing the risk of cross-contamination.

• Failing to investigate unexpected or inconsistent pathology findings that may indicate contamination before issuing a diagnosis.

Whether any particular mistake constitutes lab contamination negligence depends on the circumstances and the applicable standard of care.

The Harm Caused by a Cancer Misdiagnosis

In laboratory contamination cases, the resulting harm is often tied to an incorrect diagnosis and the treatment that follows. For example, a patient who is incorrectly diagnosed with cancer may undergo unnecessary surgery, including removal of otherwise healthy tissue or organs. Other patients may receive unnecessary chemotherapy, radiation, medications, or additional invasive testing.

These treatments carry risks, including infection, nerve damage, chronic pain, permanent loss of function, and other complications. Patients may also incur substantial medical expenses, lose income, and experience significant emotional distress.

Laboratory contamination can also contribute to delayed or missed diagnoses. If a patient’s sample is contaminated or switched with another patient’s sample, a real illness may go unnoticed and progress without appropriate treatment.

How Are Pathology Lab Errors Discovered and Investigated?

Laboratory contamination is not always immediately apparent. In some cases, contamination is discovered only after a patient undergoes additional testing or receives pathology results that conflict with the original diagnosis.

A second review of the original pathology slides may identify foreign tissue that does not belong to the patient. In certain cases, additional testing, including DNA analysis, can help determine whether the tissue originated from another person.

Investigating these claims often requires examining the original glass slides, preserved tissue blocks, pathology reports, specimen tracking records, and laboratory procedures. It may also be necessary to determine which individuals or facilities were involved in handling the specimen, how the contamination occurred, and whether any mistakes or failures contributed to the incorrect diagnosis.

Depending on where in the laboratory chain the negligence occurred, responsibility may rest with the pathology laboratory, hospital, pathologist, and/or other healthcare professionals involved in processing and interpreting the specimen.

Frequently Asked Questions

Can I sue if I was diagnosed with cancer I never had?

Possibly. If the misdiagnosis resulted from a laboratory or pathology error that fell below the standard of care, and you were harmed by it (for example, through unnecessary surgery or treatment), you may have a medical malpractice claim.

What should I do if I suspect a biopsy mix-up?

Request copies of your pathology reports and ask that the original slides and tissue blocks be preserved. A second pathology opinion, and sometimes DNA testing, can confirm whether the tissue was yours.

How long do I have to file a claim?

Medical malpractice deadlines vary by state and can be short. Speaking with an attorney promptly helps protect both your rights and the evidence.

Contact Plakas Mannos About a Potential Laboratory Contamination Claim

An incorrect laboratory result can have serious consequences, particularly when it leads to unnecessary medical procedures, treatment, or a missed diagnosis. If you or a loved one received an incorrect diagnosis due to suspected laboratory contamination, you may have grounds for a medical malpractice claim.  

At Plakas Mannos, our medical malpractice attorneys and in-house physician investigate complex medical errors, including those involving pathology and laboratory testing. We are experienced with laboratory contamination medical malpractice cases, and we work to identify how an error occurred, who may be responsible, and whether it caused preventable injury. Evidence like slides and tissue blocks can be lost or discarded over time, and legal deadlines apply, so if you suspect a lab error, don’t wait. Contact us today to discuss your options.