Sign in →

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

Reporting Name

Uroporphyrinogen III Synthase, RBC

Useful For

Diagnosis of congenital erythropoietic porphyria

Testing Algorithm

The following algorithms are available in Special Instructions:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

Specimen Type

WB Heparin


Specimen Required


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

 

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.

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

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

Clinical Information

The porphyrias are a group of inherited disorders resulting from enzyme defects in the heme biosynthetic pathway. Congenital erythropoietic porphyria (CEP) is an extremely rare, autosomal recessive porphyria that typically presents in early infancy. Also known as Gunther disease, CEP results from a deficiency of uroporphyrinogen III (co-) synthase (UROIIIS). In most cases, the disorder is suggested during the first few days or weeks of life by pink, violet, or brown urinary staining of diapers. Clinical symptoms include hemolytic anemia, hepatosplenomegaly, skin photosensitivity, scarring and blistering, red or brown dental discoloration (erythrodontia), and hypertrichosis (excess body hair). Growth and cognitive developmental delays are commonly observed in individuals with CEP. A few cases of adult-onset CEP have been reported, typically associated with a myelodysplastic syndrome.

 

The workup of patients with a suspected porphyria is most effective when following a stepwise approach. See Porphyria (Cutaneous) Testing Algorithm in Special Instructions or contact Mayo Medical Laboratories to discuss testing strategies.

Interpretation

Abnormal results are reported with a detailed interpretation that may include an overview of the results and their significance, a correlation to available clinical information provided with the specimen, differential diagnosis, recommendations for additional testing when indicated and available, and a phone number to reach a laboratory director in case the referring physician has additional questions.

Clinical Reference

1. Tortorelli S, Kloke K, Raymond K: Chapter 15: Disorders of porphyrin metabolism. In Biochemical and Molecular Basis of Pediatric Disease. Fourth Edition. Edited by DJ Dietzen, MJ Bennett, ECC Wong. AACC Press 2010, pp 307-324

2. Nuttall KL, Klee GG: Analytes of hemoglobin metabolism-porphyrins, iron, and bilirubin. In Tietz Textbook of Clinical Chemistry. Fifth edition. Edited by CA Burtis, ER Ashwood. Philadelphia, WB Saunders Company, 2001, pp 584-607

3. . Anderson KE, Sassa S, Bishop DF, Desnick RJ: X-Linked sideroblastic anemia and the porphyrias. In Disorders of Heme Biosynthesis. Edited by D Valle, AL Beaudet, B Vogelstein, et al. New York, McGraw-Hill, 2014. Accessed June 27, 2016. Available at http://ommbid.mhmedical.com/content.aspx?bookid=971&Sectionid=62638866

4. Desnick RJ, Astrin KH: Congenital erythropoietic porphyria: advances in pathogenesis and treatment. Br J Haematol 2002;117(4):779-795

Analytic Time

7 days (Not reported on Saturday or Sunday)

Method Name

High-Performance Liquid Chromatography (HPLC)

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.

Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

mml-biochemical