Porphyrins, Fractionated, Quantitative, 24‑Hour Urine

Also known as: Heptacarboxyporphyrin, Tetracarboxyporphyrin

Clinical Use

Use

Quantitative fractionated porphyrin analysis in a 24‑hour urine collection is used for diagnostic evaluation of porphyrias and related disorders. It assists in characterizing porphyrin excretion patterns across multiple porphyrin species, aiding in differential diagnosis among porphyrias such as porphyria cutanea tarda, acute intermittent porphyria, hereditary coproporphyria, variegate porphyria, and congenital erythropoietic porphyria. It may also support evaluation of elevations due to toxins or medications affecting heme synthesis.

Special Instructions

Not provided.

Limitations

Specimens exposed to light, not refrigerated, or with low pH (<4.0) may yield inaccurate results or be rejected. Certain porphyrias (e.g., EPP/XLDPP) may not be detected as their protoporphyrin is not excreted in urine. Porphyrin elevations can result from non‑porphyric causes such as drug exposures, toxins, hematologic or hepatobiliary disorders, which may complicate interpretation.

Test Details

Methodology

Other

Biomarkers

8 targets

Coproporphyrin ICoproporphyrin IIIHeptacarboxyporphyrinHexacarboxyporphyrinPentacarboxyporphyrinTotal PorphyrinsUroporphyrin IUroporphyrin III

Result Turnaround Time

3-8 days

Specimen

Urine

Volume

2 mL aliquot from 24‑hour urine

Minimum Volume

Not provided

Container

24‑hour urine container (amber, light‑protected), with sodium carbonate preservative or no preservative if properly refrigerated and protected from light

Collection Instructions

Collect a full 24‑hour urine specimen; protect from light (amber container or aluminum foil); sodium carbonate preservative preferred; keep refrigerated during collection.