Porphyrins, Quantitative, 24 Hour, Urine
Use
Preferred screening test for congenital erythropoietic porphyria and porphyria cutanea tarda, and during symptomatic periods for acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria when specimen transport will be longer than 72 hours. Includes porphobilinogen measurement, useful in evaluation of acute porphyrias.
Special Instructions
Testing algorithms are available for acute and cutaneous porphyria (Porphyria (Acute) Testing Algorithm; Porphyria (Cutaneous) Testing Algorithm).
Limitations
Not appropriate for diagnosis of conjugated or unconjugated hyperbilirubinemia (e.g., Dubin-Johnson or Rotor syndromes). Urine porphyrins and porphobilinogen are susceptible to degradation at high temperature, pH below 5.0, and exposure to light. Neither erythropoietic protoporphyria nor X‐linked dominant protoporphyria are detected. Elevation of coproporphyrin without corresponding PBG may warrant fecal porphyrin analysis.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 43116-3
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
20 to 50 mL
Minimum Volume
15 mL
Container
Amber, 60‑mL urine container (T596)
Collection Instructions
Add 5 g sodium carbonate as preservative at start (achieve pH > 7), collect 24‑hour urine, refrigerate and protect from light during collection; record volume and duration; freeze an aliquot after completion; ship in amber container protected from light.
Patient Preparation
Patient should not consume any alcohol for 24 hours before and during collection.
Causes for Rejection
All specimens are evaluated for suitability; improper preservative, pH < 5.0, or light exposure may lead to degradation.
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 7 days (Frozen, light protected) |