Porphyrins & Porphobilinogen
| Label Mnemonic: | PBGPU |
| Epic code: | LAB7365 |
| Downtime form: | Doctor/Provider Orders - Pathology Core and Specialty Care Nursery |
Commercial Mailout Laboratory
6240-8 RCP
356-8593
6240-8 RCP
356-8593
Specimen(s):
Urine (24 hr or random) More information
Specimen
Instructions:
Refrigerate during 24 hr collection in dark plastic container. The
most important aspect of specimen preservation is adequate
refrigeration during collection, storage, and transport. Protect from
light during collection, storage, and shipment. Record total volume and
collection time interval on transport tube and test request form.
Collection Medium:
) |
| Urine - 24 hour/timed dark plastic urine container |
Minimum:
24 hr collection in dark plastic container and
refrigerate during entire collection and submission to University of
Iowa Hospitals and Clinics laboratory. Containers available from
Pharmacy.
24 hr collection or random urine Preferred Minimum: 8 mL aliquot of urine Absolute Minimum: 4 mL aliquot or urine
Rejection Criteria:
Body fluids other than urine.
Turn Around
Time:
2-5 days upon receipt at reference laboratory
Reference Range:
Components: Reference Interval:
Uroporphyrin 0-4 μ mol/mol crt
Heptacarboxylate 0-2 μ mol/mol crt
Porphyrin
Coproporphyrin I 0-6 μ mol/mol crt
Coproporphyrin III 0-14 μ mol/mol crt
Porphobilinogen, Urine 0.0-8.8 μ mol/L
Porphobilinogen, 0.0-11.0 μ mol/d
Urine (24-hour)
Creatinine (24-hour) Male (mg/d) Female (mg/d)
3-8 yrs: 140-700 3-8 yrs: 140-700
9-12 yrs: 300-1300 9-12 yrs: 300-1300
13-17 yrs: 500-2300 13-17 yrs: 400-1600
18-50 yrs: 1000-2500 18-50 yrs: 700-1600
51-80 yrs: 800-2100 51-80 yrs: 500-1400
81+ yrs: 600-2000 81+ yrs: 400-1300
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).Interpretive Data:
Results are normalized to creatinine concentration and reported as a
ratio of amounts (micromoles of porphyrin/moles of creatinine).
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. 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.
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. 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.
Comments:
Submit collection dates and times on requisition. Includes Uroporphyrins, Heptacarboxylporphyrins, Coproporphyrins, Porphobilinogens, and Creatinine value. Protect from strong light; refrigerate during collection. The most important aspect of specimen preparation is adequate refrigeration during collection, storage, and transport. Samples collected according to refrigerated guidelines are viable for 4 days ONLY refrigerated.
Test
Limitations:
Urine porphyrins are useful for the evaluation of cutaneous
photosensitivity to exclude porphyria cutanea tarda (PCT). Evaluation
of neurologic and/or psychiatric symptoms associated with acute
porphyrias such as acute intermittent porphyria (AIP) requires urine
porphobilinogen (PBG) testing.
Methodology:
High Performance Liquid Chromatography/Quantitative Spectrophotometry/ Quantitative High Performance Liquid Chromatography-Tandem Mass
Spectrometry
CPT Code:
84120 Porphyrins, urine; 84110 PBG, urine
See also:
Aminolevulinic Acid, Urine (24 hour or random)
Porphobilinogen, Qualitative, Urine, Random
Aminolevulinic Acid, Urine (24 hour or random)
Porphobilinogen, Qualitative, Urine, Random
See Additional Information:
Urine Tests Requiring Preservatives, Refrigeration or Special Containers
Urine Tests Requiring Preservatives, Refrigeration or Special Containers