The ABCD test is a tool used to remember the signs of melanoma, reports the American Melanoma Foundation. The letters stand for asymmetry, border irregularity, color and diameter.
Using the ABCD test helps determine if a mole needs further attention by a doctor. If a mole is asymmetrical, one half of the mole is different from the other half. Border irregularity refers to a mole that has blurred, uneven or notched edges. A mole with uneven coloring or a diameter greater than 6 millimeters is a sign of melanoma, according to the American Melanoma Foundation.
Melanoma has several warning signs in addition to those revealed with the ABCD test, reports the American Melanoma Foundation. These warning signs include pain, bleeding, itching, oozing and swelling beyond the borders of the mole. In some cases, melanoma causes a mole to take on a scaly appearance. New nodules or bumps are also potential signs of melanoma.
Melanoma is a type of cancer that develops in specialized cells called melanocytes, states the American Cancer Society. Melanocytes produce melanin, the pigment responsible for the skin's color. Melanoma can start anywhere on the body, but it is most common on the legs of women and the trunks of men. If diagnosed early, melanoma is usually curable, but it can spread to other parts of the body if it is not treated.