Test Details
Methodology
Ion-exchange chromatography/spectrophotometry
Result Turnaround Time
3 - 5 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.
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
Record total 24-hour urine volume on the test request form. Use Porphobilinogen (PBG), Quantitative, Random Urine [003065] for random urine testing.
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.
Footnotes
Custom Additional Information
Acute attacks of acute intermittent porphyria are precipitated by drugs, including barbiturates, hydantoins, hormones, infection, and diet. The most common symptom of acute intermittent porphyria is abdominal pain. The most common sign is tachycardia.1 Subjects with the porphyrias may pass urine the color of port wine. The term porphyria derives from the Greek “porphyria,” an expression for the color purple.1 Quantitative porphobilinogen will pick up many but not all patients with acute intermittent porphyria in the latent period.
Specimen Requirements
Specimen
Urine (24-hour), frozen and protected from light
Volume
3 mL aliquot
Minimum Volume
1 mL aliquot (Note: This volume does not allow for repeat testing.)
Container
Plastic 24-hour urine container with 30 mL of 30% glacial acetic acid (Labcorp No. 23301) (optional preservative, but required if ordered with Δ-ALA) and amber plastic frozen transport tube and cap (Labcorp No. 78656).
Collection Instructions
Instruct the patient to void at 8 AM (or 8 PM) and discard the specimen. Then collect all the urine, including the final specimen voided at the end of the 24-hour collection period (ie, 8 AM [or 8 PM] the following day), in the 24-hour collection container (Labcorp No. 23301). Specimen must be kept refrigerated during collection. Measure and record on the test request form the 24-hour total volume. Mix well. Transfer the urine into a LabCorp amber plastic frozen transport tube with amber cap (Labcorp No. 78656). Label the container with the patient's name, date, and time collection started and finished. 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
0.0−1.5 mg/24 hours
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 not refrigerated during collection; specimen not protected from light; specimen not a 24-hour collection; specimen not frozen
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 003103 | Porphobilinogen, Qn, 24-Hr Ur | 003104 | Porphobilinogen,Qn,U | mg/L | 27382-1 | |
| 003103 | Porphobilinogen, Qn, 24-Hr Ur | 003105 | Porphobilinogen, 24U | mg/24 hr | 2810-0 | |
| Order Code | 003103 | |||||
| Order Code Name | Porphobilinogen, Qn, 24-Hr Ur | |||||
| Order Loinc | ||||||
| Result Code | 003104 | |||||
| Result Code Name | Porphobilinogen,Qn,U | |||||
| UofM | mg/L | |||||
| Result LOINC | 27382-1 | |||||
| Order Code | 003103 | |||||
| Order Code Name | Porphobilinogen, Qn, 24-Hr Ur | |||||
| Order Loinc | ||||||
| Result Code | 003105 | |||||
| Result Code Name | Porphobilinogen, 24U | |||||
| UofM | mg/24 hr | |||||
| Result LOINC | 2810-0 |