Test Code UPGC Uroporphyrinogen III Synthase (Co-Synthase), Erythrocytes
Reporting Name
Uroporphyrinogen III Synthase, RBCUseful 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 in Special Instructions:
Performing Laboratory

Specimen Type
WB HeparinAdvisory 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 Deaminase, Whole Blood.
Necessary Information
Include a list of medications the patient is currently taking.
Specimen Required
All porphyrin tests on erythrocytes can be performed on 1 collection tube.
Patient Preparation: Patient should abstain from alcohol for 24 hours.
Container/Tube: Green top (heparin)
Specimen Volume: Full tube
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 |
Special Instructions
Reference Values
≥75 Relative Units (normal)
See The Heme Biosynthetic Pathway in Special Instructions.
Day(s) and Time(s) Performed
Varies
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 | 11066-8 |
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 call 800-533-1710 to discuss testing strategies.
Analytic Time
7 days (Not reported on Saturday or Sunday)Reject Due To
Gross hemolysis | Reject |
NY State Approved
YesMethod 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 in Special Instructions:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.