Diagnosis of mesothelioma

Diagnosis is the process of finding out the cause of a health problem. Diagnosing mesothelioma usually begins with a visit to your family doctor. Your doctor will ask you about any symptoms you have and may do a physical exam. Based on this information, your doctor may refer you to a specialist or order tests to check for mesothelioma or other health problems.

The process of diagnosis may seem long and frustrating. It’s normal to worry, but try to remember that other health conditions can cause similar symptoms as mesothelioma. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of mesothelioma.

The following tests are usually used to rule out or diagnose mesothelioma. Many of the same tests used to diagnose cancer are used to find out the stage (how far the cancer has progressed). Your doctor may also order other tests to check your general health and to help plan your treatment.

Health history and physical exam

Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past. In taking a health history, your doctor will ask questions about your history of:

  • symptoms that suggest mesothelioma
  • being exposed to asbestos at work (occupational exposure)
  • living with someone who works with asbestos
  • previous treatment with radiation therapy to the chest or abdomen

A physical exam allows your doctor to look for any signs of mesothelioma. During a physical exam, your doctor may:

  • examine the lungs using a stethoscope
  • feel the abdomen for organs that are larger than normal
  • look for swelling in the abdomen

Find out more about physical exams.


An x-ray uses small doses of radiation to make an image of parts of the body on film. It is often the first imaging test used to look for problems in the chest.

A chest x-ray may show fluid around the lung (pleural effusion) or a thickening of the lining of the lung.

Find out more about x-rays.


An ultrasound uses high-frequency sound waves to make images of parts of the body. It is used to look for fluid in the abdomen (ascites).

Find out more about ultrasounds.

CT scan

A computed tomography (CT) scan uses special x-ray equipment to make 3-D and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures.

A CT scan is the main test used to diagnose and stage pleural and peritoneal mesothelioma. It can be used to help make decisions about treatment.

A CT scan can be used to find mesothelioma and to find out if it has spread and where it has spread. It can also be used to guide a biopsy to take tissue samples.

Find out more about CT scans.


Magnetic resonance imaging (MRI) uses powerful magnetic forces and radiofrequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-D pictures.

An MRI may be used to show where the mesothelioma is and how far it has spread if this can’t be found using a CT scan. An MRI is helpful to see if the mesothelioma has spread to the diaphragm.

Find out more about MRIs.

Removing fluid for testing

Mesothelioma can cause a buildup of fluid in the part of the body where it is growing. The doctor may remove the fluid so it can be examined for cancer cells.

Thoracentesis uses a hollow needle or tube (catheter) inserted through the skin and between the ribs to remove fluid from the space between the lungs and the wall of the chest (pleural cavity). It is used as a test for pleural mesothelioma.

Paracentesis uses a hollow needle or tube to remove fluid from the abdominal cavity. It may be done as a test for peritoneal mesothelioma.

Find out more about thoracentesis and paracentesis.


An endoscopy is done to help diagnose and stage both pleural and peritoneal mesothelioma. It allows a doctor to look inside the chest or abdomen using a tube with a light and lens on the end. This tool is called an endoscope. Different names are used for endoscopes depending on where they are used in the body.

There are several different types of endoscopy that can be used to diagnose and stage mesothelioma. A CT scan or an ultrasound may be used to guide the endoscope. During the test, small pieces of tissue, fluid and lymph nodes can be removed to be examined.

Thoracoscopy uses a thoracoscope to look inside the chest. The doctor can look for mesothelioma and where it may have spread.

Mediastinoscopy uses a mediastinoscope to look at the space between the lungs (mediastinum). It may be done if a CT scan shows that cancer may have spread to the lymph nodes between the lungs.

Bronchoscopy uses a bronchoscope to look inside the windpipe (trachea) and the large airways of the lungs (bronchi). Using a small ultrasound device at the end of the bronchoscope, the doctor can see the lymph nodes near these organs. A needle is guided by the ultrasound so the doctor can take samples of the lymph nodes and other tissues.

Laparoscopy uses a laparoscope to look inside the abdomen. The doctor can examine the peritoneum, the diaphragm and other organs in the abdomen.

Find out more about a thoracoscopy, a mediastinoscopy, a bronchoscopy and a laparoscopy.


During a biopsy, the doctor removes tissues or cells from the body so they can be tested in a lab. A report from the pathologist will confirm whether or not cancer cells are found in the sample.

There are different types of biopsies that can be used to diagnose and stage mesothelioma. A biopsy for mesothelioma is often done during an endoscopic procedure. A CT scan or an ultrasound may be used to guide the endoscope to the area.

Needle biopsy may be used to remove tissue from suspected cancer in the chest. A long hollow needle is put through the skin in between the ribs and into the pleura. Small tissue samples can be removed through the needle. A needle biopsy may also be used to take samples from the lymph nodes in the space between the lungs (mediastinum).

Surgical biopsy may be done if there is not enough tissue from an endoscopic procedure to make a diagnosis. In a thoracotomy, a cut (incision) is made in the chest to remove tissue. In a laparotomy, a cut is made in the abdomen.

Find out more about biopsies.

Pulmonary function tests

Pulmonary function tests are a group of tests that measure how well the lungs are working. They measure how much air the lungs can hold and how well the person can let air out of the lungs. Pulmonary function tests are also called lung function tests.

Pulmonary function tests may be done after mesothelioma is diagnosed to see how well your lungs are working, especially if surgery is being considered. Surgery may remove part or all of a lung, so it’s important to know if surgery can be done safely and if you will still have good lung function afterward. If your lungs are not healthy enough, surgery can’t be done.

Find out more about pulmonary function tests.

Complete blood count (CBC)

A CBC measures the number and quality of white blood cells, red blood cells and platelets. A CBC is done to give your healthcare team information about your general health.

Find out more about a complete blood count (CBC)..

Blood chemistry tests

Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can help find abnormalities. A blood chemistry test that may be used to diagnose mesothelioma is an LDH test.

Lactate dehydrogenase (LDH) is an enzyme that is found in cells. Higher levels of LDH may mean that there is tissue or cell damage somewhere in the body, which may be a sign of cancer. LDH does not diagnose mesothelioma, but it is used as a prognostic factor.

Find out more about blood chemistry tests.

Questions to ask your healthcare team

To make the decisions that are right for you, ask your healthcare team questions about diagnosis.

Expert review and references

  • Alexander HR Jr., Burk AP . Diagnosis and management of patients with malignant peritoneal mesothelioma. Journal of Gastrointestinal Oncology. 2016.
  • American Cancer Society. Malignant mesothelioma. 2016.
  • Deraco M, Elias DM, Glehen O, Helm CW, Sugarbaker PH, Verwaal VJ . Peritoneal metastases and peritoneal mesothelioma. DeVita VT Jr, Lawrence TS, & Rosenberg SA. Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2015: 115: 1761-1769.
  • Giaccone G, Thomas A, Rajan A . Mesotheliomas. Raghavan D, Blanke CD, Honson DH, et al (eds.). Textbook of Uncommon Cancer. 4th ed. Wiley Blackwell; 2012: 22: 319-334.
  • Kondola S, Manners D, Nowak AK . Malignant pleural mesothelioma: an update on diagnosis and treatment options. Therapeutic Advances in Respiratory Disease. 2016.
  • Pass HI . Biomarkers and prognostic factors for mesothelioma. Annals of Thoracic and Cardiovascular Surgery. 2012.
  • Pass HI, Carbone M, King LM, Rosenzweig KE . Benign and malignant mesothelioma. DeVita VT Jr, Lawrence TS, & Rosenberg SA. Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2015: 114: 1738-1760.
  • Stahel RA, Weder W, Lievens Y, Felip E . Malignant pleural mesothelioma: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2010.

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