OVERVIEW
What is porphobilinogen (24 hrs. urine) lab test?
It is a test included in porphyrin testing which is a group of compounds that are by-products of heme synthesis (RBC production). This test measures porphyrin precursor (precursor: substance from which another substance/cellular component is formed) called porphobilinogen (PBG) in urine. Normally porphyrins leave body via urine or stool but if there is abnormality in this process, then PBG can build up in body.
Why is porphobilinogen (24 hrs. urine) lab test done?
The test is done:
• As it helps diagnose and monitor porphyrias which affects skin and nervous system.
• It helps distinguish between cutaneous and neurologic porphyria.
• PBG test is the primary and first test done in case of neurologic porphyria
• It is done in patients showing symptoms of neurologic porphyria which include acute intermittent porphyria (AIP), hereditary coproporphyria, & variegate porphyria.
- Is porphobilinogen normally found in urine?
If taking 24 hour urine sample, then PBG is normally detected in urine in the range less than 4 milligrams/24 hours.
- What is urine PBG test?
This test basically looks for PBG in urine which is indicative of an attack or crisis of acute porphyria.
- What color is urine when excess PBG is present?
Individuals with porphyria have urine the color of port wine.
- What urine tests done for porphyria?
For its diagnosis, porphyrins and its precursors are measured in urine, blood, and stool.
- What are AIP symptoms like?
Its symptoms include severe abdominal pain; pain in chest, legs or back; constipation or diarrhea; red or brown urine; and mental changes like anxiety, confusion, hallucinations, disorientation or paranoia.
INTERPRETATION OF THE RESULTS:
- Normal range: < or = 2.2 mcmol/ 24 hours OR 0.0 – 1.5 mg/24 hours.
- In case of abnormal results, they are given with detailed interpretation and overview of the result.
You get tested for first order evaluation of suspected acute porphyria: AIP, variegate porphyria and hereditary coproporphyria.