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Test Code UPGD Uroporphyrinogen Decarboxylase (UPG D), 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 following algorithms are available in Special Instructions:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

Performing Laboratory

Mayo Medical 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

All porphyrin tests on whole blood can be performed on 1 draw tube.


Patient Preparation: Patient should abstain from alcohol for 24 hours


Preferred: Green top (sodium heparin)

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

Specimen Volume: Full tube

Collection Instructions: Immediately place specimen on wet ice.

Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Refrigerated 7 days

Reference Values

>1.0 Relative Units (normal)

0.80-0.99 Relative Units (indeterminate)

<0.80 Relative Units (porphyria cutanea tarda or hepatoerythropoietic porphyria)

Day(s) and Time(s) Performed

Tuesday, Thursday; 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


LOINC Code Information

Test ID Test Order Name Order LOINC Value
UPGD UPG Decarboxylase, WB In Process


Result ID Test Result Name Result LOINC Value
8599 UPG Decarboxylase, WB 49596-0

Reject Due To


Mild reject; Gross reject







Method Name

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


New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.