Ordering Recommendation

Distinguish among acute intermittent porphyria (AIP), variegate porphyria (VP), and hereditary coproporphyria (HCP).

Mnemonic

POR FECES

Methodology

Quantitative High Performance Liquid Chromatography

Performed

Mon, Thu

Reported

2-7 days
+

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation
Collect

Random stool.

Specimen Preparation

Protect from light during collection, storage, and shipment. Freeze specimen and wrap in foil immediately after collection. Transport 5 g stool. (Min: 1 g)

Storage/Transport Temperature

CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions

Complete timed collections (24-72 hour). Specimens stored in one gallon cans or other large containers. Liquid stool.

Remarks
Stability

Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 3 weeks

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.

Compliance Category

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

N/A

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
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • Coproporphyrinl
  • Coproporphyrins
  • Isocoproporphyrins
  • Protoporphyrin
Porphyrins, Fecal