Porphobilinogen Deaminase, RBC (Sendout)

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General Information

Lab Name
Porphobilinogen Deaminase, RBC
Lab Code
RBPBGD
Epic Name
Porphobilinogen Deaminase, Whole Blood (Sendout)
External Test Id
PBGD_
Description

Useful For: Confirmation of a diagnosis of acute intermittent porphyria (AIP).

For assistance ordering this test, contact the Laboratory Medicine Resident on-call via the paging operator at 206-598-6190. Porphobilinogen Quantitative, 24-h urine [UPBG] is the preferred initial test for diagnosis of acute intermittent porphyria.

Patient Preparation:

  • Abstinence from alcohol for at least 24 hours prior to specimen collection is essential as ethanol induces porphobilinogen deaminase (PBGD) activity, which may lead to a false-normal result.
  • Include a list of medications the patient is currently taking.
Synonyms
Acute Intermittent Porphyria, AIP, HMBS Synthase, Hydroxymethylbilane synthase, Hydroxymethylbilane Synthase, PBG, PBG-D, PBGD_, UPS, Uroporphyrinogen, Uroporphyrinogen I Synthase, Uroporphyrinogen Synthase
Components
Code Name
RBPBGR PBG Deaminase, RBC
RBPBGI PBG Deaminase, RBC Interp
RBPBGY PBG Deaminase, RBC Reviewed By

Interpretation

Method

Enzymatic End point/Spectrofluorometric

Reference Range
See individual components
Ref. Range Notes

Reference ranges have not been established for patients who are <16 years of age.

Reference Range: >=7.0 nmol/L/sec
Indeterminate: 6.0-6.9 nmol/L/sec
Diminished: <6.0 nmol/L/sec
Interferences and Limitations

Cautions: A normal result does not rule-out acute intermittent porphyria; 5% to 10% of affected individuals will have normal erythrocyte porphobilinogen deaminase activity. Additionally, enzyme activity may be increased during an acute attack; therefore, the enzyme level should be assessed when the patient is asymptomatic.

Ordering & Collection

Specimen Type
Blood
Collection

7 mL blood in GREEN TOP (Sodium Heparin) or LAVENDER TOP (EDTA) tube

Also Accepted: Dark Green Lithium Heparin (no gel)

Immediately place tube on wet ice and transport to the lab without delay.

Handling Instructions

Outside Laboratories: Refrigerate whole blood in original collection container. Transport with a cold pack.

Stability: Refrigerated (preferred): 8 days; Ambient: 7 days; Frozen: Unacceptable.

Reject Due To: Gross hemolysis.

Quantity
Requested: Entire sample
Minimum: 3 mL whole blood

Processing

Receiving Instructions

Refrigerate whole blood in original collection container.

Sendouts:

  • Order Mayo Test: PBGD_
  • Interfaced: Yes [Interface: 601; Worksheet: MARF]

Stability: Refrigerated (preferred): 8 days; Ambient: 7 days; Frozen: Unacceptable.

Reject Due To: Gross hemolysis.

Misc Sendout

Performance

Lab Department
Sendouts Mayo Lab (RF)(MARF)
Frequency
Performed: Tuesday, Thursday. Report Available: 2-4 days.
Available STAT?
No
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Billing & Coding

CPT Codes
82657
LOINC
12810-8