Test Code UPGD Uroporphyrinogen Decarboxylase, Whole Blood
Ordering Guidance
Porphyria cutanea tarda (PCT) type I (sporadic), the most common form of PCT, exhibits normal erythrocyte enzyme activity. The preferred test for diagnosis of type I is PQNU / Porphyrins, Quantitative, 24 Hour, Urine or PQNRU / Porphyrins, Quantitative, Random, Urine.
Necessary Information
Include a list of medications the patient is currently taking.
Specimen Required
Patient Preparation: Patient must not consume any alcohol for 24 hours before specimen collection. This is essential as alcohol suppresses enzyme activity for 24 hours after ingestion.
Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Lavender top (EDTA) or green top (lithium heparin)
Specimen Volume: 4 mL
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.
Useful For
Preferred test for the confirmation of a diagnosis of porphyria cutanea tarda type II and hepatoerythropoietic porphyria
Testing Algorithm
The workup of patients with a suspected porphyria is most effective when following a stepwise approach. See Porphyria (Cutaneous) Testing Algorithm or call 800-533-1710 to discuss testing strategies. If guidance is needed for an acute form of porphyria, the Porphyria (Acute) Testing Algorithm is also available.
Special Instructions
Method Name
High-Performance Liquid Chromatography (HPLC)/Incubation of Lysed Erythrocytes
Reporting Name
UPG Decarboxylase, WBSpecimen Type
Whole bloodSpecimen Minimum Volume
3 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole blood | Refrigerated (preferred) | 14 days | |
Ambient | 7 days |
Reject Due To
Gross hemolysis | Reject |
Reference Values
≥1.00 RU (normal)
0.80-0.99 RU (indeterminate)
<0.80 RU (indicative of PCT type II)
RU = Relative Units
Day(s) Performed
Tuesday, Thursday
Report Available
2 to 6 daysPerforming Laboratory
Mayo Clinic Laboratories in RochesterTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82657
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
UPGD | UPG Decarboxylase, WB | 49596-0 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
8599 | UPG Decarboxylase, WB | 49596-0 |
606379 | Interpretation (UPGD) | 59462-2 |
606380 | Reviewed By | 18771-6 |