How do you diagnose melanoma?

Biopsy. Any suspicious looking skin lesion, esp if it grows fast or changes in color or starts bleeing, needs to be biopsied. It will reveal melanoma if present.
Biopsy. As noted above, but also the acronym abcd is helpful to see which lesions should be biopsied: a- asymmetry, b-irregular borders, c-varied color, d- diameter >6mm.
Needs a Biopsy. Melanomas need to be excised as a biopsy as the diagnosis is from the pathological analysis. Clinical exam alone is not sufficient for a diagnosis.
Skin biopsy. A small biopsy is performed on the skin lesion and this is sent to a trained pathologist who examines the skin and give a diagnosis.