Porphyrins, Fecal
Also known as: POR FECES
Use
This test is useful for differentiation of acute porphyrias following a positive porphobilinogen (PBG) test, 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).
Special Instructions
Not provided.
Limitations
This fecal porphyrins assay is not a screening test. Total porphyrins are not measured. Bacterial modification of fecal porphyrins is extensive. The recommended specimen for uroporphyrin and coproporphyrin is urine. For protoporphyrin, serum is recommended. This test has not been cleared or approved by the US Food and Drug Administration; it is performed in a CLIA certified laboratory.
New York Approved
Methodology
Mass Spectrometry
Biomarkers
Coproporphyrin, Feces
AnalyteProtoporphyrin, Feces
Analyte
LOINC Codes
- 14884-1 - Porphyrins Stl-Imp
- 29267-2 - Protopor Stl-sCnt
- 29266-4 - Copro Stl-sCnt
Result Turnaround Time
2-8 days
Related Documents
For more information, please review the documents below
Specimen
Stool
Volume
5 g
Minimum Volume
1 g
Collection Instructions
Random stool. Protect from light, freeze and wrap in foil immediately after collection.
Storage Instructions
Critical frozen, separate specimens must be submitted when multiple tests are ordered.
Causes for Rejection
Complete timed collections (24-72 hour), specimens stored in one gallon cans or other large containers, liquid stool.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | Unacceptable |
| Frozen | 3 weeks |