Looking at Mesothelioma Diagnosis. Mesothelioma tests include imaging scans, such as chest X-rays and CT scans, blood tests and a biopsy. If a patient shows mesothelioma symptoms, a doctor will conduct a physical exam to check for abnormalities and refer the patient to an oncologist for testing.
If you have signs and symptoms that might indicate mesothelioma, your doctor will conduct a physical exam to check for any lumps or other unusual signs.
Your doctor may order imaging scans, such as a chest X-ray and a computerized tomography (CT) scan of your chest or abdomen, to look for abnormalities.
Based on the findings, you may undergo further testing to determine whether mesothelioma or another disease is causing your symptoms.
Biopsy
Biopsy, a procedure to remove a small portion of tissue for laboratory examination, is the only way to determine whether you have mesothelioma. Depending on what area of your body is affected, your doctor selects the right biopsy procedure for you.
Options include:
- Inserting a needle through the skin. The doctor might remove fluid or a piece of tissue with a thin needle inserted through the skin on your chest or abdomen.
- Collecting a sample of tissue during surgery. A fluid or tissue sample might be collected during an operation. The surgeon might make a small incision and insert a tube with a video camera to see inside your chest or abdomen. Special tools can be passed through the tube to collect a tissue sample.
The tissue sample is analyzed under a microscope to see whether the abnormal tissue is mesothelioma and what types of cells are involved. The type of mesothelioma you have determines your treatment plan.
How Mesothelioma Is Diagnosed
There is no clear path to a mesothelioma cancer diagnosis for every patient. Depending on the patient’s first symptoms, doctors will order different tests to narrow down the cause. In some cases, imaging tests for another illness may reveal mesothelioma. In other cases, a known history of asbestos exposure may require a tissue sample, known as a biopsy.
What Steps Lead to a Mesothelioma Diagnosis?
Not every patient will need all these tests, but the process from symptoms to a final diagnosis is generally similar for most mesothelioma patients.
- Symptoms: Symptoms of mesothelioma cause the patient to visit their primary care physician or a hospital for testing. The initial symptoms of the disease may differ for each patient and range from cough to general pain or more severe issues.
- Physical Exam: A physician takes a medical history and completes a physical exam to narrow down possible causes of illness. The exam may include visual inspection of the lungs with a scoped instrument, listening to the heart and lungs with a stethoscope, or physical tests such as light exercise or reflex reactions.
- Mesothelioma Testing: The most common first tests are radiology exams such as chest X-rays and CT scans of the chest or abdomen. These initial tests reveal abnormal results with information such as disease location and size. With this information, doctors order further testing and may offer referrals to a surgeon or oncologist.
- Confirm Diagnosis: The surgeon or oncologist uses a combination of imaging scans, blood tests and biopsies to establish a mesothelioma diagnosis. A blood test or radiology scan alone cannot confirm a diagnosis of mesothelioma. Doctors typically obtain tissue sample biopsies from surgery.
Because mesothelioma is a rare disease and has similar symptoms to more common and less severe conditions, doctors sometimes confuse it for a different illness or another type of cancer.
Initial misdiagnosis is common for mesothelioma patients. Doctors often misdiagnose pleural mesothelioma as pneumonia or lung cancer. Peritoneal mesothelioma can appear as more common abdominal cancers.
Providing your doctor with a comprehensive work history is essential to the diagnostic process. Doctors are unlikely to suspect the disease unless a patient describes a job where asbestos exposure may have occurred. Usually, mesothelioma symptoms develop 20 to 50 years after the initial asbestos exposure.
Researchers are working on ways to detect mesothelioma earlier and with less-invasive tools. According to a 2026 review authored by mesothelioma expert Dr. Harvey Pass and others, the potential to diagnose the rare disease with a breath test might one day be a reality.
Determining the extent of the cancer
Once your mesothelioma is confirmed, your doctor may recommend additional tests to understand whether your cancer has spread to your lymph nodes or to other areas of your body.
Tests may include:
- CT scans of the chest and abdomen
- Magnetic resonance imaging (MRI)
- Positron emission tomography (PET)
Your doctor determines which tests are appropriate for you. Not every person needs every test.
Your doctor uses the information from these tests to assign your cancer a stage. The stages of pleural mesothelioma are indicated using Roman numerals ranging from I to IV. A lower numeral means the cancer is more likely to be localized to the area around the lungs and the highest numeral means the cancer has spread to other areas of the body.
The cancer staging system continues to evolve and is becoming more complex as doctors improve cancer diagnosis and treatment. Your doctor uses your cancer stage to select the treatments that are right for you.
Formal stages aren’t available for other types of mesothelioma.