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

Useful For

Diagnosis of congenital erythropoietic porphyria


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

Genetics Test Information

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


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

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 should abstain from alcohol for 24 hours prior to 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)


See The Heme Biosynthetic Pathway

Day(s) Performed


Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
UPGC Uroporphyrinogen III Synthase, RBC 11066-8


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 US Food and Drug Administration.

Testing Algorithm

The following algorithms are available:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

Report Available

3 to 9 days

NY State Approved



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.