The present invention relates to a method of diagnosing, or providing a prognosis to, or for providing the likelihood of developing, malignant melanoma in a subject, the method comprising the steps of: (a) measuring two or more markers in blood perfusion dynamics at and/or around a skin lesion site; and (b) determining if the two or more markers is different to a normal value. The invention also relates to a device for diagnosing/providing a prognosis to/for malignant melanoma in a subject.