How Is Mesothelioma Diagnosed?

If you or a loved one develop symptoms associated with mesothelioma, you should ask your doctor to run tests. While the diagnostic process includes several tests, a biopsy is the only test that can confirm a mesothelioma diagnosis.

During a biopsy, doctors collect tissue samples to look for cancer cells under a microscope. A thoracoscopy is a type of biopsy that is 98% accurate at diagnosing mesothelioma. Other tests include imaging scans, blood tests and physical exams.

Medical Exam and Physical Exam

The first step is typically a physical exam. You and your doctor will discuss your medical history and any history of asbestos exposure that could put you at risk for related diseases. Based on your exposure history, your doctor will look for symptoms of mesothelioma.

Process of how mesothelioma is diagnosed
Accurately diagnosing malignant mesothelioma takes several steps and involves a variety of tests.

Doctors may use specific tools or devices during a physical exam to look for signs of disease. They will examine your chest and abdomen for signs of pain or tumors.

Imaging Tests

Radiologists use imaging tests to reveal the location and size of mesothelioma tumors around the lungs or abdomen. These scans are precise and detailed enough to determine the extent and stage of cancer, such as whether it has entered lymph nodes or other organs.


X-rays use radiation to produce basic images of areas within the body that show various densities, such as tumors or fluid.

CT Scans

Computerized axial tomography uses computer software. The software integrates hundreds of fine X-ray images into defined pictures.


Magnetic resonance imaging, or MRI, uses electromagnetic technology instead of radiation. MRIs help doctors visualize which types of tissues contain mesothelioma. It also shows whether metastasis or spreading has occurred.

The “gold standard” for mesothelioma imaging is a combination PET-CT scan with contrast dye.

Blood Tests and Biomarkers

Mesothelioma blood tests, such as MESOMARK, SOMAmer and Human MPF, can detect biomarkers of mesothelioma. These blood tests are not accurate enough to diagnose the disease.

For example, MESOMARK accurately predicted that 92% of healthy patients did not have mesothelioma. The SOMAmer mesothelioma blood test correctly diagnosed 90% of patients. 

These tests cannot replace a biopsy’s pathology report that gives the official diagnosis. Research is ongoing to develop blood tests for mesothelioma with higher accuracy.

Biopsy Procedures

A biopsy is the most definitive way to diagnose mesothelioma. During this procedure, small samples of fluid or tissue are extracted from the patient and examined under a microscope to determine the presence of cancer cells. These tissue samples inform doctors of cancer cell type and stage, helping them develop a more precise treatment plan. 

The type of biopsy depends on cancer location and patient tolerance. The process differs for each type of mesothelioma biopsy, but doctors provide anesthesia to reduce pain.


This is the most accurate biopsy technique for mesothelioma. It can accurately detect 98% of mesothelioma cases.

Cytology Test

In a cytology test, also known as a fine needle aspiration or liquid biopsy, a doctor removes fluid from a suspected tumor site. Although less accurate, it helps when it’s more difficult to get tumor tissue samples.


This test takes tissue samples of the lymph nodes around the windpipe. The test can help diagnose the stage of pleural mesothelioma.


A laparoscopy is used to examine the abdominal cavity. It collects tissue samples in patients suspected of having peritoneal mesothelioma.Pathologists look at biopsy samples under a microscope to determine cancer cell type and characteristics. They use immunohistochemical testing and other pathology techniques to identify mesothelioma cells.

Genetic Testing

While in its early phases of development for mesothelioma, sometimes doctors request genetic testing for certain patients. Research suggests a small portion of mesothelioma patients have genes that may predispose them to cancer in general. 

In the future, genetic testing may play a role in determining treatment options and predicting patient prognosis.

Why Is Mesothelioma Difficult to Diagnose?

Diagnosing mesothelioma is difficult because symptoms often mimic more common illnesses. The initial symptoms of mesothelioma also can resemble lung cancer and other chest issues.

The decades-long latency period between asbestos exposure and development of mesothelioma means 20 to 60 years may pass before symptoms arise. Patients may not mention asbestos to their doctor because they do not remember the exposure. As a result, their doctor might not consider mesothelioma as a possible diagnosis. Getting a second opinion is important because many primary care physicians and oncologists have never encountered mesothelioma. Sometimes they misdiagnose mesothelioma as a less severe disease or another cancer.

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What Does a Mesothelioma Diagnosis Mean for You?

Receiving a mesothelioma diagnosis can be a stressful moment for the person diagnosed and their loved ones. Mesothelioma is a rare and incurable cancer. 

Your primary care doctor may not have all the answers because they have likely never diagnosed it. In fact, most general doctors often misdiagnose the condition.That’s why it’s important to find a mesothelioma specialist who has diagnosed the disease for years or decades. Diagnosing mesothelioma as early as possible is crucial because it can lead to better treatment options and outcomes.

When Should You See a Doctor?

People who were exposed to asbestos at some point in their lives have a higher risk of developing mesothelioma. If you had past asbestos exposure and show chest or abdominal symptoms, you should see your primary care physician as soon as possible. And you should consider asking for a referral to a mesothelioma specialist. 

The Mesothelioma Center at has been building relationships with more than 500 mesothelioma doctors since 2006. These doctors have spent years, even decades, diagnosing mesothelioma.   

Once you meet with a mesothelioma specialist, they can create a treatment plan tailored to your type and stage.

Your Treatment Options After a Mesothelioma Diagnosis

Treatment for mesothelioma may include surgery, chemotherapy, radiation therapy or immunotherapy.

The treatments your doctor recommends depend on where the tumors formed, their cell type and stage of progression.

  • Chemotherapy: Chemotherapy is available to patients diagnosed at any stage.
  • Immunotherapy: Immunotherapy is also available to patients diagnosed at any stage.
  • Radiation Therapy: Radiation therapy is most often a part of multimodal therapy for mesothelioma patients diagnosed in early stages.
  • Surgery: Surgery is available for patients diagnosed in the early stages of mesothelioma.

Doctors specializing in mesothelioma provide access to innovative therapies and clinical trials. You may consider different treatments available through clinical trials.

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Coping With a Mesothelioma Diagnosis

Receiving a mesothelioma diagnosis can feel overwhelming to patients and their families. One of the best coping strategies is to build a mesothelioma support network. 

Reach out to family, friends, neighbors and community members. A strong support system will help you get through the challenges of a mesothelioma diagnosis.

Ask your cancer center if they have a social worker who can help you access local resources. They may also have a therapist available for counseling. Inquire about cancer support groups as well. Talking with others who understand your challenges is a healthy way to process stress.


Common Questions About Your Mesothelioma Diagnosis

What should you do if you think you have mesothelioma?

If you have a history of asbestos exposure and develop mesothelioma symptoms, make an appointment with your primary care physician. If they believe you need further testing, they will refer you to a specialist.

How long does it take to get a mesothelioma diagnosis?

The average time from initial symptoms, such as shortness of breath or chest pain, to a mesothelioma diagnosis is approximately three months.

How do you prepare for a mesothelioma biopsy?

Stop taking any blood-thinning medication at least five days before a biopsy. Wear loose clothing to the appointment, and plan to have a designated driver take you home. Do not eat or drink anything six hours before your appointment. Plan to spend several hours undergoing the biopsy. Some biopsies, such as thoracoscopy, require at least a one-night stay in the hospital.

Why is it important to get a second opinion?

Seeking a second opinion from a mesothelioma specialist is important because they have expertise in diagnosing and treating the disease. A specialist may offer a more accurate diagnosis and recommend better treatment options than a general oncologist.