If you’ve noticed a new or changing mole that you’re worried may be melanoma, it’s a good idea to have your doctor take a closer look. They can run some tests to determine whether it might be a sign of melanoma or another type of skin cancer. Your doctor can also refer you to a dermatologist (skin specialist) to make a diagnosis.

In this article, we’ll discuss the seven tests used to diagnose melanoma.

1. Physical Exam

Your doctor will start by taking your medical history and performing a physical exam. They may ask about your personal and family history of melanoma and other types of skin cancer. Some people have a higher risk of melanoma, especially if they have a close relative who’s had it. You should also let your doctor know if you have a history of sunburns or use a tanning bed.

Your doctor will also ask about the suspicious spot or mole. Be sure to tell them if you’ve experienced any pain, itching, or bleeding around the spot. Your doctor will take a closer look at it, taking notes on its shape, size, color, and what the surrounding skin looks like. They’ll also check for any bleeding, crusting, or oozing.

Your doctor may also feel for any nearby lymph nodes around the concerning spot. Lymph nodes are small, bean-shaped organs of the immune system. If your melanoma has spread into a nearby lymph node, the node may be larger than normal. Common places to check lymph nodes include the underarms, neck, and groin.

2. Dermoscopy

During your physical exam, your doctor may use dermoscopy to take a closer look at any suspicious spots on your skin. A dermatoscope uses light and a special magnifying lens to look at your skin cells and structures underneath your skin. Your doctor can use pictures from dermoscopy to monitor moles or spots over time.

3. Skin Biopsy

The only way to confirm a melanoma diagnosis is to take a tissue sample with a skin biopsy.

The goal of a skin biopsy is typically to remove as much of the suspicious spot as possible. This will help your doctor make the most accurate diagnosis. The biopsy sample is then sent to a lab to be looked at under a microscope. If the pathologist (tissue specialist) finds melanoma cells, it confirms your melanoma diagnosis.

There are several types of biopsies, and your doctor will choose the one best suited for your lesion. They’ll take the location and size of the skin area into consideration.

Types of biopsy used to check for melanoma include:

• Shave biopsy — Uses a surgical blade to shave off skin growths that are only on the top layers of the skin
• Punch biopsy — Uses a tool similar to a hole punch to remove deeper layers of skin
• Excisional biopsy — Cuts out the entire area of affected skin plus a small margin of healthy skin
• Incisional — Cuts out only one section of the tumor

An excisional biopsy is usually the preferred method of biopsy if your doctor thinks you have melanoma. In this procedure, the doctor cuts out the whole tumor and some normal skin around it to make sure they get all the cancerous cells. Afterward, a pathologist looks at the tissue under a microscope to see how serious the melanoma is.

4. Sentinel Lymph Node Biopsy

If you’ve been diagnosed with stage 2 melanoma, your doctor may recommend additional testing. Stage 2 melanomas haven’t spread into nearby lymph nodes yet, but they’re at a higher risk of doing so. Other reasons your doctor may recommend additional testing include if you have ulcerations (open wounds) near your melanoma, or if the cells are dividing very quickly.

A sentinel lymph node biopsy is a diagnostic test used to check whether cancer has spread to nearby lymph nodes. Your doctor will inject a small amount of radioactive tracer near your melanoma. After some time, they’ll check to see whether the tracer traveled into any lymph nodes.

Any lymph nodes that contain the tracer are referred to as sentinel lymph nodes. This is because these are the first lymph nodes that the melanoma would spread to. Your doctor will also inject a dye in the same area as the tracer. They’ll then perform surgery to look for any dyed lymph nodes to be removed.

The sentinel lymph nodes are then sent to the lab to be analyzed. If the pathologist finds melanoma cells in the lymph nodes, you’ll need the other nearby nodes removed. If there aren’t any melanoma cells in the sentinel nodes, you won’t need additional surgery.

5. Molecular Testing

Doctors also use molecular testing to look for gene changes or mutations in melanoma cells. These changes — known as biomarkers — can affect your treatment plan. For example, half of all cutaneous (skin) melanomas have changes in the BRAF gene. Doctors can prescribe certain targeted therapies that only work if you have a BRAF mutation.

Other mutations your doctor may look for in your melanoma cells include:

• N-RAS — Found in 20 percent of melanomas
• NF-1 — Found in 10 percent to 15 percent of melanomas
• C-KIT — Found in certain types of melanoma, such as mucosal and acral-lentiginous melanoma

Mutations in ROS1, ALK, and NTRK genes are less common. However, scientists have developed targeted therapies to treat cancers with these gene changes.

6. Imaging Tests

Imaging tests typically aren’t needed for diagnosing early-stage melanoma. Your doctor may order these tests if they think your melanoma may have spread to other parts of your body. This spread is known as metastasis.

Magnetic resonance imaging (MRI) uses high-powered magnets to take detailed images of the body. An MRI is usually used to look for melanoma that has spread to the brain or spinal cord.

Computed tomography (CT or CAT) scans use X-rays taken at several angles to create three-dimensional images of the body. CT scans are used to check for metastases to other internal organs like the liver or lungs.

Positron emission tomography (PET) uses a radioactive sugar that’s injected into a vein and marks tumors and cancer cells. The PET scan then uses a specialized camera that finds the radioactive areas in your body.

7. Blood Tests

Blood tests normally aren’t used to diagnose melanoma. However, your doctor may measure your lactate dehydrogenase (LDH) levels before starting a treatment. A higher level of LDH may mean your melanoma is at a more advanced stage.

Talk With Others Who Understand

MyMelanomaTeam is the social network for people with melanoma and their loved ones. On MyMelanomaTeam, members come together to ask questions, give advice, and share their stories with others who understand life with melanoma.

What tests did your doctor use to diagnose your melanoma? Share your experience in the comments below, or start a conversation by posting on your Activities page.