The doctor will first ask about the history and in particular whether in the past worked with asbestos. The occupations with the highest risk are workers in shipbuilding and in the heating industry. In the physical examination, a damping of the lung are found due to the moisture. About this area of damping is less breath sounds heard. Sometimes the tumor through the chest wall outward growth.

On lung fluid and swelling can picture the lung membranes seen. This is almost always unilateral. A CT scan of the chest gives better information at the tumor in the lung membranes is. Importantly, pathological examination to determine whether this moisture or changes in the lung membranes based on a truly malignant mesothelioma. Therefore, the moisture and a piece of the lung membranes examined. This can be done by a needle through the skin to absorb some moisture. Typically, this fluid a bloody appearance. The piece is a blind pleural biopsy done through the skin or through a keyhole surgery (thoracoscopy).

These studies done to diagnose malignant mesothelioma and to secure to the extent of the tumor to determine in relation to possible treatment. After this, a conservative ruling on life expectancy. Because of the far-reaching implications of the diagnosis malignant mesothelioma and the difficulties in correctly interpreting the histological findings, a national body (the mesothelioma panel) that derived tissue co-evaluate and likely to reveal the likelihood of a malignant mesothelioma. Capturing the extent of the tumor is done using the T (for tumor size and location), N (for all lymph nodes are affected or not) and M (metastasis to other organs) status. On this basis, a structure created in four stages.