Do I have to get some blood tests before doing a puva treatment?

Phototherapy. Puva, means psoralen ultraviolet a. This is a treatment for certain skiin diseases, like psoriasis or vitiligo, where a chemical made from a plant, called psoralen, is ingested or applied to the skin rash, and then the patient is exposed to certain kinds of light, called ultraviolet light a. Some dermatologists check the patients liver , and for lupus, by doing a blood test before puva is started.