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Order Code LABUPGD Uroporphyrinogen Decarboxylase, Whole Blood

Additional Codes

Mayo Test Code: UPGD

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

A stepwise approach is typically most effective when evaluating patients with suspected porphyria. See Porphyria (Cutaneous) Testing Algorithm 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.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Whole blood


Ordering Guidance


Porphyria cutanea tarda (PCT) type I (sporadic), the most common form of PCT, exhibits normal erythrocyte enzyme activity. The preferred test for diagnosis of PCT 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: For 24 hours before specimen collection, patient must not consume any alcohol. This is essential 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: 4 mL; full tube


Specimen Minimum Volume

3 mL

Specimen Stability Information

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

Reference Values

≥1.00 RU (Normal)

0.80-0.99 RU (Indeterminate)

<0.80 RU (Indicative of porphyria cutanea tarda type II)

 

RU = Relative Units

Day(s) Performed

Tuesday

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

Genetics Test Information

Uroporphyrinogen decarboxylase is deficient in cases of type II porphyria cutanea tarda (PCT). Enzyme analysis is uninformative in sporadic PCT cases.

Method Description

This procedure is performed by incubation of lysed red blood cells with aminolevulinic acid as the substrate followed by analysis of the porphyrins formed.(Unpublished Mayo method)

Reject Due To

Gross hemolysis Reject

Method Name

High-Performance Liquid Chromatography (HPLC)

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.