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Test ID UPGDW Uroporphyrinogen Decarboxylase (UPG D), Washed Erythrocytes

Useful For

Diagnosis of porphyria cutanea tarda type II and hepatoerythropoietic porphyria

 

Due to limited stability for this test, the preferred test for analysis of UPGD enzyme is UPGD / Uroporphyrinogen Decarboxylase (UPG D), Whole Blood.

Genetics Test Information

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

 

This test should only be ordered when the specimen will be received at Mayo Medical Laboratories within 24 hours of collection. The preferred test for analysis of UPGD enzyme is UPGD / Uroporphyrinogen Decarboxylase (UPG D), Whole Blood.

Method Name

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

Reporting Name

UPG Decarboxylase, RBC

Specimen Type

Washed RBC


Specimen Required


All porphyrin tests on erythrocytes can be performed on 1 draw tube.

 

Collection Container/Tube:

Preferred: Green top (heparin)

Acceptable: Lavender top (EDTA)

Submission Container/Tube: Plastic vial

Specimen Volume: Washed erythrocyte suspension

Collection Instructions:

1. Patient should abstain from alcohol for 24 hours.

2. Collect and process whole blood specimen as follows:

a. Immediately place specimen on wet ice.

b. Transfer entire specimen to a 12-mL graduated centrifuge tube.

c. Centrifuge specimen for 10 minutes at 2,000 rpm.

d. Record volume of packed cells and the total volume of the specimen.

e. Discard supernatant plasma.

f. Wash erythrocytes 2 times by resuspension with 5 mL of cold 0.9% saline, discarding supernatant after each washing.

g. Resuspend packed cells to the original total volume with 0.9% saline. Invert specimen gently to mix.

Additional Information:

1. Volume of packed cells and total volume of erythrocyte suspension (red cells + saline) are required.

2. Include a list of medications the patient is currently taking.


Specimen Minimum Volume

1 mL of washed and resuspended erythrocytes

Specimen Stability Information

Specimen Type Temperature Time
Washed RBC Frozen 24 hours

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.

Performing Laboratory

Mayo Medical Laboratories in Rochester

CPT Code Information

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
UPGDW UPG Decarboxylase, RBC In Process

 

Result ID Test Result Name Result LOINC Value
31892 UPG Decarboxylase, RBC 49596-0

Testing Algorithm

The following algorithms are available in Special Instructions:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

Forms

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.