Porphobilinogen (PBG), Quantitative, Random Urine
•PBG Random Urine, Quantitative
Appropriate test to rule out acute intermittent porphyria (AIP) and other acute attack types of porphyrias associated with neurologic and/or psychiatric symptoms.
Detect porphyrias and porphyrinurias. Acute intermittent porphyria is characterized by excretion of porphobilinogen and Δ-aminolevulinic acid in urine during acute attacks but not during latency. Increased porphobilinogen may be caused also by variegate porphyria or hereditary coproporphyria. Increased urine values are seen in the intoxication porphyrias (heavy metals, halogenated solvents, certain drugs).
Urine (random), frozen and protected from light
Plastic urine container with 0.5 mL of 30% glacial acetic acid (optional preservative, but required if ordered with Δ-ALA) and amber plastic frozen transport tube and cap.
On collection of random urine, it is advisable not to use first voided morning specimen, late evening specimen after 8 PM, or specimen obtained following excessive fluid intake. Transfer the urine into an amber plastic frozen transport tube with amber cap. If ordered with Δ-ALA, pH must be <6. Label the container with the patient’s name and date. The specimen should be frozen immediately and maintained frozen until tested. (If amber tube and cap are not available, cover a clear plastic transport tube completely from top to bottom with aluminum foil. Identify the specimen with the patient’s name directly on the transport tube and the outside of the aluminum foil. Secure with tape.)
Freeze immediately and protect from light. Urine is stable when preserved with 30% glacial acetic acid and frozen for one month or refrigerated for 24 hours.
Specimen exposed to light; specimen not received frozen.