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Porphyrins, Fractionated, Quantitative and Porphobilinogen, 24-Hour Urine
Test CodeQ17198
Includes
Porphyrins, Fractionated, Quantitative, 24-Hour Urine (Coproporphyrin I, Coproporphyrin III, Heptacarboxyporphyrin, Hexacarboxyporphyrin, Pentacarboxyporphyrin, Uroporphyrin I, Uroporphyrin III, Total Porphyrins)
Porphobilinogen, Quantitative, 24-Hour Urine
CPT code 81050 may be added at an additional charge for volume measurement
Porphobilinogen, Quantitative, 24-Hour Urine
CPT code 81050 may be added at an additional charge for volume measurement
Preferred Specimen
4 mL of 24-hour urine containing sodium carbonate, collected in a plastic leak-proof container
Minimum Volume
2 mL
Instructions
Urine for a 24 hour
collection should be alkalinized with sodium carbonate
(5g Na2CO3) to a pH of 6-7. The urine should be
refrigerated and protected from light during the
collection. If sample is to also be used for ALA,
maintain pH between 6-7.
collection should be alkalinized with sodium carbonate
(5g Na2CO3) to a pH of 6-7. The urine should be
refrigerated and protected from light during the
collection. If sample is to also be used for ALA,
maintain pH between 6-7.
Transport Temperature
Refrigerated (cold packs)
Specimen Stability
Room temperature: Unacceptable
Refrigerated: 7 days
Frozen: 30 days
Refrigerated: 7 days
Frozen: 30 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Not protected from light • pH <4.0 (acidified urine)
Methodology
High Performance Liquid Chromatography (HPLC) • Chromatography/Mass Spectrometry
Setup Schedule
Set up: Sun, Tues-Fri; Report available: 6-8 days
Clinical Significance
Urinary Porphobilinogen is the first step in the diagnosis of acute porphyrias such as acute intermittent porphyria (AIP). AIP is an autosomal dominant disorder characterized by deficiency of porphobilinogen deaminase. An acute attack usually includes gastrointestinal disturbance and neuropsychiatric disorders.
