There is a lot of confusion, even in the medical community regarding the color of urine produced by people with porphyria. It is generally known that the name porphyria refers to purple urine; but, it is a misnomer, as far as I can tell.
It is my understanding that the highest incidence of purple urine is with those unfortunate sufferers of the cutaneous types of porphyria.
I have one of the acute porphyrias (or Variegate, which has a little of both acute and cutaneous) and have had many severe attacks; only a few times has my urine been other than a shade of yellow. The worst time it was purple (according to my wife…I don’t remember it); and, during a couple very bad attacks it was a shade of orange.
I’ve tried the trick of putting a container of my urine in the sun; but, it has never turned colors, even when I am having an attack.
However, when I am feeling porphyric, it is pretty common for my urine to be darker than normal. The goal is to drink enough water to keep it clear, with very little color.
One other note, on urine, is that a 24 hour sample of urine can be tested to determine if someone has porphyria. However, it is not unusual for this test to yield a false negative. In my case, the 24 hour urine sample proved that I have porphyria. The hematologist that ordered the test told me that it was the first time that he has seen porphyria determined this way…and, I wasn’t even having an attack or feeling porphyric.