Test Details
Methodology
Chromatography/spectrophotometry
Result Turnaround Time
3 - 6 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Porphobilinogen (PBG) normalized to mg/gram Creatinine units
Use
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 delta aminolevulinic acid in urine during acute attacks, but not during latency. Increased urine values are seen in the intoxication porphyrias (heavy metals, halogenated solvents, certain drugs).
Special Instructions
For 24-hour urine testing, order Porphobilinogen (PBG), Quantitative, 24-Hour Urine [003103].
Limitations
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Specimen Requirements
Specimen
Urine (random), frozen and protected from light
Volume
3 mL
Minimum Volume
1 mL (Note: This volume does not allow for repeat testing.)
Container
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 (Labcorp No. 78656).
Collection Instructions
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 a Labcorp amber plastic frozen transport tube with amber cap (Labcorp No. 78656). 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.)
To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
Reference Range
0.2–2.2 mg/g Creat.
Storage Instructions
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.
Causes for Rejection
Specimen exposed to light; specimen not received frozen
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 003065 | Porphobilinogen, Qn, Random Ur | 24446-7 | 003066 | Porphobilinogen, Qn, Random Ur | mg/L | 24446-7 |
| 003065 | Porphobilinogen, Qn, Random Ur | 24446-7 | 003067 | Creatinine, U | mg/dL | 2161-8 |
| 003065 | Porphobilinogen, Qn, Random Ur | 24446-7 | 003068 | PBG/Creatinine Ratio | mg/g Creat. | 13797-6 |
| Order Code | 003065 | |||||
| Order Code Name | Porphobilinogen, Qn, Random Ur | |||||
| Order Loinc | 24446-7 | |||||
| Result Code | 003066 | |||||
| Result Code Name | Porphobilinogen, Qn, Random Ur | |||||
| UofM | mg/L | |||||
| Result LOINC | 24446-7 | |||||
| Order Code | 003065 | |||||
| Order Code Name | Porphobilinogen, Qn, Random Ur | |||||
| Order Loinc | 24446-7 | |||||
| Result Code | 003067 | |||||
| Result Code Name | Creatinine, U | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2161-8 | |||||
| Order Code | 003065 | |||||
| Order Code Name | Porphobilinogen, Qn, Random Ur | |||||
| Order Loinc | 24446-7 | |||||
| Result Code | 003068 | |||||
| Result Code Name | PBG/Creatinine Ratio | |||||
| UofM | mg/g Creat. | |||||
| Result LOINC | 13797-6 |