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Porphobilinogen (PBG) Deaminase, Erythrocyte
Ordering Recommendation
Use to confirm a diagnosis of acute intermittent porphyria (AIP) following a positive urine porphobilinogen (PBG) test. Use to evaluate disease risk in family members of an individual with a confirmed diagnosis of AIP.
New York DOH Approval Status
Specimen Required
Perform automated hemoglobin on EDTA whole blood before preparing for transport.
Lavender (EDTA) or pink (K2EDTA).
Transport 3 mL whole blood. (Min: 1 mL)
Frozen.
Body fluid other than EDTA preserved whole blood. Clotted specimens.
Automated hemoglobin result must be included with specimen.
Ambient: 4 hours; Refrigerated: 1 week; Frozen: 1 month
Methodology
Quantitative Enzymatic Assay/Fluorometry
Performed
Tue, Thu
Reported
1-6 days
Reference Interval
Adult: 2.10-4.30 mU/g Hb
Interpretive Data
Porphobilinogen (PBG) deaminase (hydroxymethylbilane synthase or uroporphyrinogen I synthase) is expressed in units of mU per gram hemoglobin at 37°C. In persons genetically susceptible to acute intermittent porphyria (AIP), PBG deaminase concentrations are approximately half of reference values. Normal concentrations of erythrocyte PBG deaminase may include abnormal forms of hepatic PBG deaminase.
Standard
Note
This test is most useful for family studies to determine which family members are at risk for acute intermittent porphyria and is best performed in association with a specimen from the proband. Because of ambiguous results, this test is not generally recommended for diagnosis.
Hotline History
CPT Codes
82657
Components
| Component Test Code* | Component Chart Name | LOINC |
|---|---|---|
| 0099550 | Porphobilinogen Deaminase RBC | 49228-0 |
| 2011401 | Hemoglobin (client supplied) | 718-7 |
Aliases
- Acute Intermittent Porphyria Enzyme
- HMB Synthase
- HMBS
- Hydroxymethylbilane Synthase
- PBG-D
- Porphyria Enzyme
- Uroporphyrinogen I Synthase
- Uroporphyrinogen Synthase
