Porphobilinogen, Quantitative, Random Urine : 6329

Test Code
UPBGRN or 6329

Alias/See Also
PBG; Porphyria

CPT Codes

Random urine.
2 mL (1 mL minimum) urine (no preservative) collected in a plastic leak-proof container.
Random clean catch urine collected with 0.5g sodium carbonate (Na2CO3) per 100 mL of sample.

Transport Container
Urine should be refrigerated and protected from light.

Whenever possible, the specimen should be collected during an acute episode because porphobilinogen (PBG) may decrease rapidly upon remission. PBG may also degrade when samples are exposed to UV light for extended periods, or are transported at ambient temperature. If an amber collection jug/urine cup is not available, the sample must be protected from light by completely wrapping the container in aluminum foil. PBG is most stable at pH 6-7, but samples may be sent with or without preservative. All results should be interpreted in the context of clinical findings, relevant history, and other laboratory data.

Transport Temperature

Specimen Stability
Ambient: Unacceptable; Refrigerated: 7 days; Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Not protected from light.

Chromatography/Mass Spectrometry

Setup Schedule
Tuesday & Thursday & Saturday

Report Available
3-6 days (From receipt at performing laboratory)

Reference Range
Pediatric        <0.36 mg/g creat
Adult              <0.22 mg/g creat

Clinical Significance
Urinary Porphobilinogen is the first step in the diagnosis of 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.

Performing Laboratory
Quest Diagnostics

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.