Mesothelioma Diagnosis

Doctors use several types of imaging tests, blood tests, and biopsies to diagnose mesothelioma. Since mesothelioma is such a rare disease, it’s important to get a correct diagnosis as soon as possible. An accurate diagnosis can help you access life-extending treatments to improve life expectancy.

How Is Mesothelioma Diagnosed?

To make a mesothelioma diagnosis, doctors will often first monitor initial symptoms such as dry cough, chest pain, shortness of breath, weight loss, and more. Once the doctor rules out that more common conditions are not causing symptoms, they may test for mesothelioma.

Mesothelioma is diagnosed through a series of tests including:

  • Imaging tests
  • Blood tests
  • Biopsies

Malignant mesothelioma is a very rare disease and may be mistaken for more common conditions such as bronchitis or pneumonia. This can make it difficult to get an accurate and timely diagnosis.

A mesothelioma diagnosis confirms the presence of mesothelioma in the body. On the other hand, a mesothelioma prognosis is the likely course that the disease will take.

If you’ve recently been diagnosed with mesothelioma or believe you may have it, download our free Questions to Ask Your Doctor Checklist. This checklist can help you prepare any questions you have for your doctor and make sure you get the answers you need.

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Quick Facts About Diagnosing Mesothelioma

  • Approximately 3,000 people are diagnosed with mesothelioma each year, according to the American Society of Clinical Oncology (ASCO)
  • Mesothelioma is not usually diagnosed until 20-50 years after exposure to asbestos
  • Most people diagnosed with mesothelioma are 65 years old or older
  • Mesothelioma can sometimes be diagnosed in younger adults, teenagers, and children, as noted in case studies from the Journal of Pediatric Surgery and the peer-reviewed journal Digestive Diseases and Sciences

If you suspect that mesothelioma may be the cause of your symptoms, talk with your doctor. Early detection and diagnosis are key to receiving potentially life-saving treatment.

A Mesothelioma Diagnosis Video Thumbnail

Nurse Amy Fair discusses what to expect after getting a diagnosis of mesothelioma. This holistic disease affects not only the victim but the family and the caretaker too. View Transcript.

Duration: 1 min 43 sec

The most important thing folks that have been diagnosed with mesothelioma need to do is to take one minute and one day at a time. To get a diagnosis and try to fast forward about the when’s and the what’s and the how’s of what’s going to happen next month, or in six months or a year, can be very overwhelming.

When talking with families of someone that’s been diagnosed with mesothelioma, I encourage them to first let that particular person go through the stages of the feelings that they’re going to go through with this disease.

It’s important that the caregivers stay healthy too. They need to still be able to get away. They still need to be able to surround themselves with support through their family and through their church and through their friends.

Many times, when caregivers are struggling with the change of life that they are going through with this disease, I encourage them to reach out to; if they have local support groups there some of the oncologists can refer them to some local support groups. If they do not have those resources, then I do refer them directly to a mesothelioma support group.

The clients I have work with that have made the most profound impression with me are the clients that, they just needed someone to talk to and sometimes it’s not about medical, it’s not about the side effects of chemotherapy, it’s just sharing a memory of their loved one.

I get cards from them for different occasions, and there’s always a note that says that we made a difference.

Diagnostic Tests by Mesothelioma Type

Doctors use specific techniques and equipment to make a mesothelioma diagnosis depending on where the cancer is in the body.

Here are the common tests used for each type of mesothelioma:

  • Pleural mesothelioma: CT scans, MRIs, and ultrasounds can be used to determine if cancer is present in the pleura (lung lining). PET scans may be used to see how far the cancer has spread. Pulmonary function tests can also test the efficiency of the lungs.
  • Peritoneal mesothelioma: Peritoneal mesothelioma forms in the abdominal lining. If this cancer is suspected, doctors typically start with a CT scan of the abdomen. Blood samples may be taken to help rule out other conditions.
  • Pericardial mesothelioma: This type of mesothelioma forms in the lining of the heart. Chest X-rays, MRI scans, and echocardiograms may be used to see if cancer tumors have started to develop around the heart. Most cases are only diagnosed after the patient has died since this type is extremely rare.
  • Testicular mesothelioma: Doctors may use X-rays, ultrasounds, and biomarkers to diagnose this type of cancer.

No matter which type of mesothelioma is suspected, biopsies are always conducted after these tests to see if cancerous cells are present in the affected area.

Mesothelioma Imaging Tests

Imaging tests are generally the most common tool used in diagnosing mesothelioma. Doctors use these tests to see where possibly cancerous fluids, tumors, and/or masses have formed within the body.

While the imaging tests listed below are important in the diagnosis process, the American Cancer Society (ACS) notes that more tests will be needed to confirm if someone has cancer.

X-Ray Scans

An X-ray uses electromagnetic radiation to create a picture of the inside of the body. According to the ACS, X-rays are typically the first test a doctor will use to see if a patient has pleural or peritoneal mesothelioma.

Doctor Reviewing X-ray
X-rays can reveal the initial signs of both pleural and peritoneal mesothelioma.

X-rays can show:

  • Calcium deposits
  • Fluid buildup in the lungs (pleural effusion)
  • Thickening of the lining of the lungs or abdomen (peritoneum)
  • Other abnormalities that may indicate mesothelioma

CT Scans

Similar to X-rays, a computerized tomography (CT) scan creates a comprehensive image of the body that can locate potentially cancerous growths.

A CT scan takes numerous images and creates a computerized view of the body from multiple angles. CT scans for cancer usually require contrast to outline different body organs.

MRI Scans

A magnetic resonance imaging (MRI) scan is similar to a CT scan, but it uses radio and magnetic waves instead of light waves to see if cancerous tumors may be present.

If you receive an MRI, you can expect to lay inside a tube-like scanner for up to an hour while the scan occurs.

MRI Machine
MRI scans can detect the presence and location of cancerous tumors.

PET Scans

A positron emission tomography (PET) scan uses a low-dose of a sugary radioactive substance to detect cancer cells. This substance will be injected into the patient’s body about one hour before the scan.

Cancer cells grow at a rapid pace and consume a larger quantity of sugar than other cells. The PET scan can show which cells (if any) are consuming more sugar — and, in turn, may be cancerous — and where these cells are located.

The scan can also show if these cells have begun to spread throughout the body.


An echocardiogram is a specialized form of ultrasound that uses sound waves to take an image. After a gel is placed on the chest, a wand sends sound waves into the body to create a picture on a monitor.

Echocardiograms are frequently used to help confirm a pericardial mesothelioma diagnosis. A doctor may request an echocardiogram to see how well the heart is functioning or if they suspect fluid buildup around the heart.

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Mesothelioma Blood Tests and Biomarkers

In addition to imaging scans, doctors can also use blood tests to see if mesothelioma cells may be present within the body.

Mesothelioma increases the levels of certain substances within the blood, including fibulin-3, soluble mesothelin-related peptides (SMRPs), and other substances. These substances can be detected through various mesothelioma blood tests.

Outside of blood tests, many future techniques for determining a mesothelioma diagnosis are focused on biomarkers, which use substances or processes to identify abnormalities in the body.

Learn more about the different types of mesothelioma blood tests below.


The most common mesothelioma blood test is the SMRP test, which goes by its trademarked name MesoMark®. This test looks for heightened SMRP levels that develop in the blood if mesothelioma cells are present.

Blood work Analysis
SMRP tests can measure blood levels to detect the presence of mesothelioma cells.

N-ERC Test

Like MesoMark, this test determines if a substance called N-ERC (mesothelin) is present within the patient’s blood.

The N-ERC test is considered more accurate than the SMRP test in identifying cancer. However, it is not as helpful when diagnosing mesothelioma specifically since the presence of N-ERC may also be a sign of other types of cancer.

Osteopontin Test

Osteopontin is a naturally occurring protein that increases when a person has mesothelioma.

An osteopontin test can determine whether a patient has cancer but does not indicate what type. Therefore, osteopontin tests that come back positive will require additional testing to confirm a mesothelioma diagnosis.

MPF Test

The MPF test is used to detect the megakaryocyte potentiating factor (MPF), a protein found in the blood of mesothelioma patients. Scientists are still studying why there are high levels of MPF in mesothelioma patients.

Mesothelioma Biopsies

The only conclusive way to make a diagnosis of mesothelioma is to perform a biopsy of tissue or fluid cells. A mesothelioma biopsy generally involves collecting a tissue or fluid sample from a possible cancerous growth and sending it to a laboratory to be examined for cancer cells under a microscope.

Doctors look at the tissue or fluid sample under a microscope to definitively diagnose mesothelioma.

Doctors typically take a fluid sample from the affected area to look for cancer cells, as fluid buildup is a common symptom of both pleural and peritoneal mesothelioma.

Examining fluid may not be enough to conclusively diagnose mesothelioma since cancer cells may not always be present, or could look like inflammation. The ACS notes that doctors usually need a tissue sample to definitively make a mesothelioma diagnosis.

Learn more about the different types of mesothelioma biopsies below.


Doctors create a small incision in the chest and use video-assisted thoracoscopic surgery (VATS) to extract a biopsy sample. This type of mesothelioma biopsy is often preferred over others for its accuracy.

According to a study from Mansoura University in Egypt, the diagnostic accuracy rate of flexi rigid thoracoscopy reached 93.6% for 100 patients with undiagnosed pleural effusions.

Fine Needle Biopsy

Fine needle biopsies use a long and skinny needle to collect sample cells. This type of biopsy is valued for its ability to access hard-to-reach locations in the body, such as the lungs and the heart.

Other Types of Mesothelioma Biopsies

Although thoracoscopy and fine needle biopsies are the two most common types, other techniques may be used to diagnose mesothelioma in some cases.

Additional types of biopsies include:

  • Endobronchial ultrasound needle biopsy: Doctors insert a tube down the windpipe of a sedated patient to examine the airway and collect tissue samples from the lymph nodes.
  • Laparoscopy: Doctors use a small tube with a light and camera to look inside the abdomen to locate tumors.
  • Mediastinoscopy: Doctors take a sample of the area between the two lungs (the mediastinum) if they believe the cancer has spread to nearby lymph nodes between the two lungs.

Doctors can recommend which types of biopsies will work best to confirm a mesothelioma diagnosis.

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Mesothelioma Diagnosis Challenges

Doctors may face several challenges when diagnosing mesothelioma in a patient. Since mesothelioma takes decades to develop and is very rare, it can be difficult to accurately diagnose the disease.

Learn about possible mesothelioma diagnostic challenges below.

Latency Period

Mesothelioma is very unusual since it takes 20-50 years after asbestos exposure before noticeable symptoms appear.

This long latency period means that victims may not even remember being exposed to asbestos-containing products. Victims may also not suspect that relatively mild symptoms could be caused by mesothelioma.

Patients should always tell their doctor if they were exposed to asbestos – even if their symptoms are mild.


Since mesothelioma symptoms are often vague and mild, doctors may initially mistake mesothelioma for a wide range of more common diseases.

Mesothelioma may be misdiagnosed as:

  • Bronchitis
  • Coronary artery disease
  • Chronic obstructive pulmonary disease (COPD)
  • Crohn’s disease
  • Emphysema
  • Irritable bowel syndrome (IBS)
  • Testicular infection
  • Other forms of cancer

Doctors use many different mesothelioma testing methods to make sure their diagnosis is accurate. A mesothelioma misdiagnosis can have dangerous — even deadly — consequences for a patient.

If you believe you were misdiagnosed, seek a mesothelioma second opinion from an experienced specialist.

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Mesothelioma Stage

Staging also presents a challenge when making a mesothelioma diagnosis. Symptoms can be mild or non-existent in the early stages of mesothelioma.

Most people are diagnosed in the later stages of mesothelioma after the symptoms have worsened. By then, chances of long-term survival are decreased since treatment options are limited and focus on palliative (pain-relieving) care.

According to the American Society of Clinical Oncology (ASCO), 13% to 16% of patients diagnosed with early-stage mesothelioma will still be alive after 5 years. By contrast, 5% to 10% of patients with late-stage mesothelioma survive 5 years after diagnosis.


A mesothelioma prognosis (patient health outlook) is greatly affected by a mesothelioma diagnosis. For example, if the cancer is diagnosed after it has spread throughout the body, the prognosis will likely be worse.

Fortunately, there are many mesothelioma survivors that have beaten the odds and surpassed their initially poor life expectancy. Doctors will be able to estimate — but not completely guarantee — the expected prognosis after a mesothelioma diagnosis for this reason.

Next Steps After a Mesothelioma Diagnosis

Doctor Comforting Elderly Male

If you or a loved one have been diagnosed with mesothelioma or believe you may have it, we can help you get the answers you need.

If you have any additional questions about mesothelioma, contact us today. We can answer any of your questions and connect you with resources that best fit your needs.

How is mesothelioma diagnosed?

Mesothelioma is diagnosed through a series of tests. Specialists generally diagnose mesothelioma through imaging tests, blood tests, and biopsies.

What is the most accurate way to diagnose mesothelioma?

One of the most accurate testing methods to diagnose mesothelioma is a biopsy. A biopsy is the only way to confirm the presence of mesothelioma. This procedure involves collecting fluid or tissue samples from the affected area to test for cancer cells under a microscope.

Can a blood test show mesothelioma?

Yes, but the most definitive way to diagnose mesothelioma is through a biopsy. Blood tests can show levels of substances generally present in mesothelioma patients such as fibulin-3 and SMRPs.

If your doctor detects these substances in your blood tests, they will then order a biopsy to test for cancer cells.

Is mesothelioma difficult to diagnose?

No. While it may be difficult, skilled mesothelioma specialists can usually make a proper diagnosis. If you think you might have been misdiagnosed, seek a second opinion from a specialist.

Why does it take so long to diagnose mesothelioma?

Asbestos has a very long latency period. It can take 20-50 years for symptoms of mesothelioma to be present. Due to the long latency period of asbestos, many mesothelioma patients are not diagnosed until the later stages of the disease. This is why early detection and medical intervention is important to extend life expectancy.

What should I do if I think I was misdiagnosed?

If you believe you have mesothelioma and were misdiagnosed, it is important to seek a second opinion. Getting an accurate diagnosis is crucial to ensure you are getting the treatment you need. Use our Doctor Match to find a mesothelioma specialist near you to get a mesothelioma diagnosis.

Reviewed by:Dr. Mark Levin

Certified Oncologist and Hematologist

  • Fact-Checked
  • Editor

Mark Levin, MD has nearly 30 years of experience in academic and community hematology and oncology. In addition to serving as Chief or Director at four different teaching institutions throughout his life, he is also still a practicing clinician, has taught and designed formal education programs, and has authored numerous publications in various fields related to hematology and oncology.

Dr. Mark Levin is an independently paid medical reviewer.

Mesothelioma Hope was founded by a team of passionate health advocates to educate people about this aggressive form of cancer. Mesothelioma affects thousands of people each year. Our team works tirelessly to give hope to those impacted by mesothelioma. Learn more about operating principles and our Editorial Guidelines.

8 References
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  2. How is MALIGNANT MESOTHELIOMA DIAGNOSED? (n.d.). Retrieved July 14, 2021, from

  3. Malignant mesothelioma STAGES. (n.d.). Retrieved July 07, 2021, from

  4. Mesothelioma. (2020, October 20). Retrieved July 14, 2021, from

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  6. Nhs choices. (n.d.). Retrieved July 14, 2021, from,surgery%20or%20minimally%20invasive%20surgery

  7. Scharf, J., Lees, G., & Sergi, C. (2015, September 08). Malignant pleural mesothelioma in a child. Retrieved July 19, 2021, from

  8. Tests to diagnose mesothelioma. (2021, June 03). Retrieved July 14, 2021, from

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