Special Precautions/Comments:

Protect from light and send to laboratory urgently.

Ideally collect urine sample while patient is symptomatic.

Additional Information:

Porphyrias are a rare heterogeneous group of mostly inherited metabolic disorders, which are sub-classified as acute or non-acute. They are caused by abnormalities of enzymes in the haem biosynthetic pathway, which leads to accumulation of substrates. They may cause acute attacks, light-sensitive skin disease or both. Clinical signs of acute attacks include severe abdominal pain, vomiting, constipation, tachycardia, hypertension and psychosis. Porphyrias can be life-threatening and diagnosis can be challenging.  

A urine porphyrin screen consists of total urine porphyrin and the porphobilinogen (PBG). Increased urinary PBG is strongly suggestive of acute prophyria because it accumulates during an acute attack. Further porphyria studies can be performed following a positive or borderline urine porphyrin screen.