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Order Code LABGOR, UPGC Uroporphyrinogen III Synthase (Co-Synthase), Erythrocytes

Reporting Name

Uroporphyrinogen III Synthase, RBC

Useful For

Diagnosis of congenital erythropoietic porphyria

 

This test is not useful for diagnosis of acute intermittent porphyria (AIP).

Testing Algorithm

The following algorithms are available:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

WB Heparin


Ordering Guidance


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 Deaminase, Whole Blood.



Necessary Information


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

2. Date of transfusion, if performed



Specimen Required


All porphyrin tests on erythrocytes can be performed on one collection tube.

 

Patient Preparation: Patient must not consume any alcohol for 24 hours before specimen collection.

Container/Tube: Green top (sodium or lithium heparin)

Specimen Volume: 4 mL

Collection Instructions: Immediately place specimen on wet ice.


Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
WB Heparin Refrigerated 7 days

Reference Values

≥75 Relative Units (normal)

 

For more information see The Heme Biosynthetic Pathway

Day(s) Performed

Wednesday

CPT Code Information

82657

Genetics Test Information

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

Method Description

Washed cells are incubated with aminolevulinic acid as substrate and the series I and III porphyrin isomers formed are measured. The proportion of series III isomers formed in relation to total porphyrins (I + III isomers) represents the uroporphyrinogen III synthase activity. The values are reported as Relative Units.(Unpublished Mayo method)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.