If the patient is a female and the porphyria seems to be intermitent...then check all hormone levels. Women on the Pill or women who have been on the Pill for long periods of time can show signs of Porphyria.
Also....check the liver enzyme levels...we have had patients show up with this that did not know they had Hep C as firstline causation.
All heps were checked as a matter of fact all front line stuff was checked and has been checked for the past four years.