A number of tests may be performed to investigate symptoms of sarcoma and confirm a diagnosis.

Some of the more common tests include:

• a physical examination
• imaging of the area with the lump, which may include X-ray, computed tomography (CT) scans, magnetic resonance imaging (MRI), ultrasound, positron emission tomography (PET) scans, bone scans, and endoscopy (use of a thin tube with a light and camera to look at the lining of the gastrointestinal tract – for gastrointestinal stromal tumours)
• taking a sample of tissue (biopsy) for examination under a microscope.

After sarcoma has been diagnosed, other tests may be done to find out whether the cancer cells have spread within the body and, if so, how far. This is called staging of the tumour, and is an important step in planning treatment.

Tests that might be used as part of staging include the ones listed above, as well as testing of blood samples and bone marrow samples (for bone sarcomas).