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Test ID UPGC Uroporphyrinogen III Synthase (Co-Synthase) (UPG III S), Erythrocytes

Useful For

Diagnosis of congenital erythropoietic porphyria

Genetics Test Information

This test is not appropriate for assessment of acute abdominal pain.

Highlights

Congenital erythropoietic porphyria (CEP) is a disease usually seen in pediatric patients.

 

In our testing experience over the last 10 years, fewer than 5 adult patients have been diagnosed with CEP associated with a myelodysplastic syndrome.

Method Name

High-Performance Liquid Chromatography (HPLC)

Reporting Name

Uroporphyrinogen III Synthase, RBC

Specimen Type

WB Heparin


Advisory Information


This test is most appropriately used for pediatric patients.

 

This test measures uroporphyrinogen (UPG) III synthase to confirm congenital erythropoietic porphyria, which is typically seen in early infancy. It does not measure UPG I synthase (also known as porphobilinogen deaminase), the enzyme deficient in acute intermittent porphyria (AIP). For AIP (and UPG I synthase), order PBGD_ / Porphobilinogen (PBG) Deaminase, Whole Blood.



Necessary Information


1. Physician name and phone number are required. Due to the high frequency of incorrect test orders, all UPGC test requests are confirmed by a genetic counselor as appropriate prior to the test being run. A letter is faxed to the ordering physician with options for alternative testing. If a response is not received from the physician within 1 week, the test will be canceled and the specimen will be held for 1 month.

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



Specimen Required


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

 

Patient Preparation: Patient should abstain from alcohol for 24 hours.

Container/Tube: Green top (heparin)

Specimen Volume: Full tube

Collection Instructions:

1. Patient should abstain from alcohol for 24 hours.

2. Immediately place specimen on wet ice.

Additional Information:

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

2. This test is most appropriately used for pediatric patients.

3. Due to the high frequency of incorrect test orders, all UPGC test requests are confirmed by a genetic counselor as appropriate prior to the test being run. A letter is faxed to the ordering physician with options for alternative testing. If a response is not received from the physician within 1 week, the test will be canceled and the specimen will be held for 1 month.


Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time
WB Heparin Refrigerated 7 days

Reference Values

≥75 Relative Units (normal)

 

See The Heme Biosynthetic Pathway in Special Instructions.

Day(s) and Time(s) Performed

Varies

The order for this test is confirmed by a genetic counselor prior to the test being run.

Performing Laboratory

Mayo Medical Laboratories in Rochester

CPT Code Information

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
UPGC Uroporphyrinogen III Synthase, RBC In Process

 

Result ID Test Result Name Result LOINC Value
80288 Uroporphyrinogen III Synthase, RBC 11066-8

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.

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.