Distinguish among acute intermittent porphyria (AIP), variegate porphyria (VP), and hereditary coproporphyria (HCP).
Quantitative High Performance Liquid Chromatography
New York DOH Approval Status
Protect from light during collection, storage, and shipment. Freeze specimen and wrap in foil immediately after collection. Transport 5 g stool. (Min: 1 g)
CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.
Complete timed collections (24-72 hour). Specimens stored in one gallon cans or other large containers. Liquid stool.
Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 3 weeks
|Coproporphyrin, Feces||0-45 nmol/g dry weight|
|Protoporphyrin, Feces||0-100 nmol/g dry weight|
This test is useful for differentiation of acute porphyrias following a positive porphobilinogen (PBG), or diagnosis or strong suspicion of acute porphyria. Fecal porphyrin excretion usually is not elevated in acute intermittent porphyria (AIP), but massive increases of fecal coproporphyrin are seen in hereditary coproporphyria (HCP). Fecal protoporphyrin and coproporphyrin excretion is increased in variegate porphyria (VP).
This fecal porphyrins assay is not a screening test. Total porphyrins are not measured.
For additional information, access the Porphyrias topic in ARUP Consult (arupconsult.com).
This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.
Laboratory Developed Test (LDT)
Bacterial modification of fecal porphyrins is extensive. The recommended specimen for uroporphyrin and coproporphyrin is urine (random or 24-hour). Refer to Porphyrins, Fractionation & Quantitation, Urine (ARUP test code 2002058). The recommended specimen for protoporphyrin is serum. Refer to Porphyrins, Serum Total (ARUP test code 0080429).
|Component Test Code*||Component Chart Name||LOINC|
|0020806||Porphyrin Fecal Interpretation||14884-1|