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Order Code MISMA - GOKEY UPGC Uroporphyrinogen III Synthase (Co-Synthase) (UPG III S), Erythrocytes

Additional Codes

Mayo Test ID:  UPGC

Reporting Name

Uroporphyrinogen III Synthase, RBC

Useful For

Diagnosis of congenital erythropoietic porphyria

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: Immediately place specimen on wet ice.

Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time
WB Heparin Refrigerated 7 days

Reject Due To


Mild reject; Gross reject






Ambient or frozen whole blood

Reference Values

≥75 Relative Units (normal)


See The Heme Biosynthetic Pathway in Special Instructions.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Day(s) and Time(s) Performed


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

Method Name

High-Performance Liquid Chromatography (HPLC)

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


LOINC Code Information

Test ID Test Order Name Order LOINC Value
UPGC Uroporphyrinogen III Synthase, RBC 12811-6


Result ID Test Result Name Result LOINC Value
80288 Uroporphyrinogen III Synthase, RBC 12811-6

Testing Algorithm

The following algorithms are available in Special Instructions:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm