Porphyrins, Fecal
Ordering Recommendation
Distinguish among acute intermittent porphyria (AIP), variegate porphyria (VP), and hereditary coproporphyria (HCP).
New York DOH Approval Status
Specimen Required
Random stool.
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
Methodology
Quantitative High Performance Liquid Chromatography (HPLC)
Performed
Mon
Reported
2-8 days
Reference Interval
Test Number |
Components |
Reference Interval |
---|---|---|
Coproporphyrin, Feces | 0-45 nmol/g dry weight | |
Protoporphyrin, Feces | 0-100 nmol/g dry weight |
Interpretive Data
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)
Note
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).
Hotline History
Hotline History
CPT Codes
84126
Components
Component Test Code* | Component Chart Name | LOINC |
---|---|---|
0020806 | Porphyrin Fecal Interpretation | 14884-1 |
0099825 | Protoporphyrin, Feces | 29267-2 |
0099826 | Coproporphyrin, Feces | 29266-4 |
Aliases
- Coproporphyrinl
- Coproporphyrins
- Isocoproporphyrins
- Protoporphyrin