Porphyria Screens

The laboratory performs a urine porphyrin screen in house whilst blood samples (required for latent porphyria or cutaneous porphyria) and all samples from known porphyria patients are referred to a specialist laboratory. The sample required and interpretation depends upon the clinical scenario;

• ? acute porphyria in a symptomatic patient: Send urine to lab for a porphyrin screen (PBG and total urine porphyrin). A negative PBG screen in a symptomatic patient excludes an acute porphyria as the cause of the symptoms.
• ? acute porphyria in an asymptomatic patient (or >3 days post-symptoms): Send urine to lab for a porphyrin screen (PBG and total urine porphyrin) and an EDTA blood to refer to a specialist laboratory to rule out latent/resolving porphyria.
• ? bullous porphyria (skin fragility): Send urine to lab for a porphyrin screen (PBG and total urine porphyrin). A negative total urine porphyrin excludes porphyria as a cause of skin fragility.
• ? acute photosensitivity (EPP): Send EDTA blood to lab for referral to a specialist laboratory.
• Asymptomatic patient with a family history of porphyria: Send urine, blood & faecal samples to QEHB laboratory for referral to a specialist laboratory.

All samples for porphyria investigations must be protected from the light otherwise there are a risk of a false negative result. Clinical details MUST be provided with a request for investigation of porphyria. This is to enable appropriate investigation and reporting by both QEHB lab and the specialist laboratories.

In the event of a positive or equivocal urine porphyrin screen, additional samples (EDTA blood/faeces) may be requested for referral to a specialist laboratory.