Melanoma Diagnostic Tests


Once the presence of melanoma is confirmed, your doctor may wish to perform other melanoma diagnostic tests, especially if you have symptoms or if there is concern that the melanoma may have spread.

Blood Tests

Blood tests are not used to diagnose or find melanoma. Abnormal levels of certain enzymes in the blood can be an indicator of disease. Lactate dehydrogenase (LDH) is a blood test. An abnormally high LDH level may indicate metastases. If your LDH level is increased, your doctor may perform additional tests to search for metastases. LDH levels provide information about the prognosis of melanoma.


Different forms of imaging allow doctors to see internal tissues and organs. This helps determine if the melanoma has spread anywhere in the body. Imaging is not used for people with stage 0 melanoma or low-risk stage I disease. For intermediate-risk stage I disease and stage II disease, imaging is used mostly to evaluate specific symptoms, such as pain. Imaging is not a routine test in early melanoma. For stage III and stage IV disease, imaging is used to evaluate specific symptoms. It is also used to assess the degree of spread of the melanoma.

The type of imaging depends on symptoms and the likely location of melanoma spread.

• Chest x-ray: A chest x-ray may be performed for some stage I and II melanomas. It is often performed for stage III and IV melanomas.

• Computed tomography (CT) scan: A CT scan takes multiple x-rays of part of the body from different angles. This produces a three-dimensional image. Injection of a contrast agent helps highlight the area of concern. A CT scan is the best type of imaging to detect melanoma in the lung.

• Magnetic resonance imaging (MRI): An MRI uses radio waves and magnets to take pictures of organs and other parts of the body. An MRI is the best type of imaging to find melanoma in the brain.

• Positron emission tomography (PET) scan: An injection of radioactive glucose, or sugar, is given before this test. The scan identifies areas with the most glucose, especially cancer cells, which collect glucose.


You may want to ask your doctor these questions about tests for melanoma:

• What tests do you suggest for me?
• Where will the tests take place? Do I need to go to the hospital?
• How long do the tests take?
• Will it hurt? Will I be given a local anesthetic?
• What happens if I’m pregnant?
• Do I need to prepare for tests?
• Do I need to bring a list of my medications?
• Can I bring someone with me?
• How long does it take to recover? Do I need any medication after the tests?
• When will I know the results? Who will explain them to me?
• If a biopsy is done, will I get a copy of the pathology report?
• If I have cancer, who will talk with me about the next steps? When?

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