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How Stage IV is Diagnosed

Step 1: Physical Examination 

The patient should get a physical examination of the entire skin, lymph node areas, and organs.


For more information on the doctor's examination click here.

Step 2: Tests to Make Certain

The doctor may order various other tests to confirm a diagnosis of melanoma and/or determine if or where the disease has spread:


  • X-ray. An x-ray is a picture of the inside of the body. For instance, a chest x-ray can help doctors determine if the cancer has spread to the lungs.

  • Blood tests. Blood levels of LDH may be tested to help determine if the cancer has spread. 

Step 3: Additional Tests

Sometimes the following special scanning tests (similar to x-rays in that they provide special images of the inside of the body and require no surgery) may also be performed:


  • Ultrasound. An ultrasound uses sound waves to create pictures of the internal parts of the body, including collections of lymph nodes (called basins) and soft tissue.

  • Computed tomography (CT or CAT) scan. A CT scan creates a 3-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed view that shows any abnormalities or tumors.

  • Magnetic resonance imaging (MRI). An MRI is done with a special scanning machine that uses magnetic fields, not x-rays, to produce detailed images of the body.

  • Positron emission tomography (PET) scan. In a PET scan, a special fluid made of sugar is injected into the body, which can be seen by a special scanner. Cancer cells usually absorb sugar more quickly than normal cells, so they may light up on the PET scan. PET scans are often used in addition to a CT scan, MRI, and physical examination.


For more on the diagnosis of melanoma click here.


For more on the staging of melanoma click here.


  • In stage IV, the melanoma has spread to distant sites (metastasized).
  • Because of this, doctors are not looking at thickness or lymph node involvement to make a diagnosis or prognosis.
  • Instead, they're looking at the location, number, and size of the metastases and the serum LDH level.