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Test Code UPGD Uroporphyrinogen Decarboxylase, Whole Blood

Reporting Name

UPG Decarboxylase, WB

Useful For

Preferred test for the confirmation of a diagnosis of porphyria cutanea tarda type II and hepatoerythropoietic porphyria

Testing Algorithm

The workup of patients with a suspected porphyria is most effective when following a stepwise approach. See Porphyria (Cutaneous) Testing Algorithm in Special Instructions or call 800-533-1710 to discuss testing strategies. If guidance is needed for an acute form of porphyria, the Porphyria (Acute) Testing Algorithm is also available in Special Instructions.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Whole blood


Advisory Information


Porphyria cutanea tarda (PCT) type I, the most common form of PCT, exhibits normal RBC enzyme activity. The preferred test for diagnosis of type I is PQNU / Porphyrins, Quantitative, 24 Hour, Urine or PQNRU / Porphyrins, Quantitative, Random, Urine.



Necessary Information


Include a list of medications the patient is currently taking.



Specimen Required


Patient Preparation: Patient should abstain from alcohol for 24 hours. Abstinence from alcohol is essential for at least 24 hours as alcohol suppresses enzyme activity for 24 hours after ingestion.

Container/Tube:

Preferred: Green top (sodium heparin)

Acceptable: Lavender top (EDTA) or green top (lithium heparin)

Specimen Volume: Full tube


Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Refrigerated (preferred) 14 days
  Ambient  7 days

Reference Values

≥1.0 RU (normal)

0.80-0.99 RU (indeterminate)

<0.80 RU (indicative of PCT type II)

RU = Relative Units

Day(s) and Time(s) Performed

Tuesday; 8 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
UPGD UPG Decarboxylase, WB 49596-0

 

Result ID Test Result Name Result LOINC Value
8599 UPG Decarboxylase, WB 49596-0
606379 Interpretation (UPGD) 59462-2
606380 Reviewed By 18771-6

Reject Due To

Gross hemolysis Reject

Method Name

High-Performance Liquid Chromatography (HPLC)/Incubation of Lysed Erythrocytes

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 in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.