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HelpTest Code PBG D WB Porphobilinogen Deaminase, Whole Blood
Reporting Name
PBG Deaminase, WBSCH Clinical System Name: Porphobilinogen (PBG) Deaminase, Whole Blood
Useful For
Confirmation of a diagnosis of acute intermittent porphyria
Ordering Guidance
This test is for diagnosis of acute intermittent porphyria. Porphobilinogen deaminase, also known as uroporphyrinogen I synthase, is commonly confused with uroporphyrinogen III synthase, the enzyme deficient in congenital erythropoietic porphyria (CEP). For CEP cases, order UPGC / Uroporphyrinogen III Synthase (Co-Synthase), Erythrocytes.
Necessary Information
1. Patient’s age is required
2. Include a list of medications the patient is currently taking.
Specimen Required
Patient Preparation: Patient must not consume any alcohol for 24 hours before specimen collection. This is essential as ethanol induces porphobilinogen deaminase activity, which may lead to a false-normal result.
Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Lavender top (EDTA) or green top (lithium heparin)
Specimen Volume: 4 mL
Collection Instructions: Refrigerate specimen as soon as possible.
Specimen Type
Whole bloodSpecimen Minimum Volume
3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Refrigerated (preferred) | 8 days | |
| Ambient | 7 days |
Day(s) Performed
Tuesday
TAT: 4 - 6 days
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Method Name
Enzymatic End Point/Spectrofluorometric
Method Description
Measurement of porphobilinogen deaminase (PBGD) activity is based on the measurement of the rate of synthesis of uroporphyrin from porphobilinogen (PBG) in incubated, lysed erythrocytes. Low yield of uroporphyrin from PBG indicates a deficiency of PBGD.(Ford RE, Ou CN, Ellefson RD. Assay for erythrocyte uroporphyrinogen I synthase activity, with porphobilinogen as substrate. Clin Chem. 1980;26(8):1182-1185; Bustad HJ, Kallio JP, Vorland M, et al. Acute Intermittent Porphyria: An Overview of Therapy Developments and Future Perspectives Focusing on Stabilisation of HMBS and Proteostasis Regulators. Int J Mol Sci. 2021;22(2):675. doi:10.3390/ijms22020675)
Reference Values
Reference ranges have not been established for patients who are younger than 16 years.
≥7.0 nmol/L/sec
6.0-6.9 nmol/L/sec (indeterminate)
<6.0 nmol/L/sec (diminished)
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82657
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PBGD_ | PBG Deaminase, WB | 12810-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 4022 | PBG Deaminase, WB | 12810-8 |
| 28400 | Interpretation | 59462-2 |
| 606470 | Reviewed By | 18771-6 |
Testing Algorithm
The following algorithms are available:
-Porphyria (Acute) Testing Algorithm
Special Instructions
Report Available
2 to 8 daysReject Due To
| Gross hemolysis | Reject |
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.