Porphyrins and Porphobilinogen (PBG), Urine
Ordering Recommendation
Evaluate patients with suspected porphyria presenting with neurologic/psychiatric, abdominal, and/or cutaneous symptoms.
New York DOH Approval Status
Specimen Required
24-hour or random urine. Refrigerate 24-hour specimens during collection.
Protect from light. Transfer 8 mL aliquot to an ARUP amber transport tube. (Min: 4 mL) Record total volume and collection time interval on transport tube and test request form.
Frozen.
Body fluids other than urine.
Ambient: Unacceptable; Refrigerated: 4 days; Frozen: 1 month
Methodology
Quantitative High Performance Liquid Chromatography (HPLC)/Quantitative Spectrophotometry/Quantitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
Performed
Sun-Sat
Reported
2-5 days
Reference Interval
Test Number |
Components |
Reference Interval |
|||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Creatinine, Urine - per 24h |
|
||||||||||||||||||||||
Porphobilinogen, Urine - ratio to CRT | 0.0 - 0.2 mmol/mol CRT | ||||||||||||||||||||||
Uroporphyrin - ratio to CRT | 0-4 µmol/mol CRT | ||||||||||||||||||||||
Heptacarboxylate - ratio to CRT | 0-2 µmol/mol CRT | ||||||||||||||||||||||
Porphobilinogen (PBG), Urine -per 24h | 0.4 - 1.5 µmol/d | ||||||||||||||||||||||
Coproporphyrin I - ratio to CRT | 0-6 µmol/mol CRT | ||||||||||||||||||||||
Coproporphyrin III - ratio to CRT | 0-14 µmol/mol CRT |
Interpretive Data
Results are normalized to creatinine concentration and reported as a ratio of amounts (micromoles of porphyrin/moles of creatinine).
Porphobilinogen (PBG), Urine
Results for random urine specimens are normalized to creatinine (CRT) concentration and reported as a ratio of amounts (millimoles of PBG/mole of creatinine).
Porphobilinogen (PBG) in a random urine specimen is used to evaluate an attack of acute porphyria. Slight increases in urinary PBG are associated with acute porphyrias other than acute intermittent porphyria (AIP) and may indicate a resolving or treated acute porphyria.
Urinary PBG in excess of two times the upper reference limit is consistent with acute porphyria.
Per 24h calculations are provided to aid interpretation for collections with a duration of 24 hours and an average daily urine volume. For specimens with notable deviations in collection time or volume, ratios of analytes to a corresponding urine creatinine concentration may assist in result interpretation.
Laboratory Developed Test (LDT)
Note
Urine porphyrins are useful for the evaluation of cutaneous photosensitivity to exclude porphyria cutanea tarda (PCT). Urine porphobilinogen (PBG) is useful for the evaluation of neurologic and/or psychiatric symptoms to exclude acute porphyrias such as acute intermittent porphyria (AIP).
Hotline History
Hotline History
CPT Codes
84120; 84110
Components
Component Test Code* | Component Chart Name | LOINC |
---|---|---|
0020207 | Creatinine, Urine - per volume | 2161-8 |
0020208 | Creatinine, Urine - per 24h | 2162-6 |
0080262 | Porphobilinogen (PBG), Urine -per volume | 2811-8 |
0080365 | Uroporphyrin - ratio to CRT | 32043-2 |
0080366 | Heptacarboxylate - ratio to CRT | 38175-6 |
0080369 | Porphobilinogen (PBG), Urine -per 24h | 14882-5 |
0080459 | Porphyrin Urine Interpretation | 49292-6 |
0097110 | Total Volume | 19153-6 |
0097111 | Hours Collected | 30211-7 |
2002059 | Coproporphyrin I - ratio to CRT | 45313-4 |
2002061 | Coproporphyrin III - ratio to CRT | 45315-9 |
3017599 | Porphobilinogen, Urine - ratio to CRT | 34357-4 |
3017600 | Porphobilinogen Interpretation | 93479-4 |
Aliases
- Coproporphyrin
- Heptacarboxyl Porphyrin
- Hexacarboxyl Porphyrin
- PBG
- Pentacarboxyl Porphyrin
- Porphobilinogen
- Porphyrins, Quantitative, 24-Hour Urine
- Urine Quantitative
- Uroporphyrin