Clinical suspicion of acute or non-acute porphyria.
Usually requested together with urine porphyrins and PBG.
May include otherwise unexplained abdominal pain, neurological or psychotic features, skin lesions.
Fresh faecal sample protected from light.
Paediatric sample - 1 gm faeces (approx). Protect from light.
Chilled (2 - 8 degrees Celsius)
If overnight - Chilled (2 - 8 degrees Celsius)
1 gm faeces, walnut size sample Protect from light. Fridge
Raised faecal porphyrins may indicate an underlying porphyria, although may be secondary to bacterial contamination of the stool or haemorrhage into the GI tract.
If raised, HPLC profiling will usually be added for metabolite profiling which will give an indication of underlying porphyria and which type.
For example, faecal iso-coproporphyrin is regarded as a hallmark of porphyria cutanea tarda (PCT).
Faecal CIII:CI ratio is elevated in hereditary copro-porphyria (HCP).
Urine and blood porphyrins often provide useful adjunctive diagnostic information.
Note that a raised urine PBG is the diagnostic hallmark of an acute attack of porphyria.
A negative urine PBG during an acute symptomatic episode excludes acute porphyria as the cause.
Of the acute porphyrias (AIP, VP, HCP), faecal porphyrins are not raised in AIP.
<200umol/Kg dry weight
Extraction, Spectrophotometric scan
$27.23 (Exclusive of GST)
Porphyrins are very light sensitive. Place sample pottle into a brown paper bag or wrap in foil.
For adequate screening tests for porphyria we require:
Blood: 2-5 ml heparinised blood (T34)
Urine: 10-15 ml fresh random specimen
Faeces: A stool minimum 10 g (walnut size)
Specimens should be wrapped in foil, placed in a paper bag and not exposed to direct sunlight.
Urgent tests by arrangement.