Uroporphyrinogen Decarboxylase, Whole Blood
Use
The Uroporphyrinogen Decarboxylase test is primarily used for the confirmation of a diagnosis of porphyria cutanea tarda type II and hepatoerythropoietic porphyria. These are inherited disorders associated with enzyme defects in the heme biosynthetic pathway, resulting in symptoms such as cutaneous photosensitivity, chronic blistering lesions on sun-exposed skin, and liver dysfunction. The test measures the deficiency of the enzyme uroporphyrinogen decarboxylase in erythrocytes and hepatocytes, crucial for differentiating between types of porphyria and guiding treatment decisions.
Special Instructions
Patients must avoid alcohol consumption for 24 hours before specimen collection, as it suppresses enzyme activity. Include a list of medications the patient is currently taking with the specimen. New York clients require informed consent for genetic testing.
Limitations
This enzyme analysis is not informative in cases of sporadic type I porphyria cutanea tarda (PCT), as patients exhibit normal erythrocyte enzyme activity. Exposure to significant heat can decrease enzyme activity, potentially leading to diagnostic errors. Alcohol consumption close to specimen collection can cause false-positive results, underscoring the importance of patient preparation instructions.
New York Approved
Methodology
Other
Biomarkers
LOINC Codes
- 49596-0
- 49596-0
- 59462-2
- 18771-6
Result Turnaround Time
3-9 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
4 mL
Minimum Volume
3 mL
Container
Green top (sodium heparin) preferred; lavender top (EDTA) or green top (lithium heparin) acceptable
Patient Preparation
Patient must not consume any alcohol for 24 hours before specimen collection.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |