Laboratory: Clinical Biochemistry  (METABOLIC)
Test Name:
PORPHYRINS, TOTAL, PEDIATRIC, RANDOM, URINE - (U)
Test Code: MISC
Clinical Information:
Test Indications: Random collections normalized to urinary creatinine may be of some clinical use in patients who cannot collect a 24-hour specimen, typically small children. Therefore, this random test is offered for children <16 years old.
 
This test must be approved by the Biochemical Geneticist prior to collection.
 
This test is used in the differential diagnosis of porphyria.
 
The porphyrias are a group of inherited disorders resulting from enzyme defects in the heme biosynthetic pathway. Depending on the specific enzyme involved, various porphyrins and their precursors accumulate in different specimen types. The patterns of porphyrin accumulation in erythrocytes and plasma and excretion of the heme precursors in urine and feces allow for the detection and differentiation of the porphyrias.
 
If the urine porphyrins screen is positive, quantitation is done as a reflex test.
 
The reflex test includes quantitation of coproporphyrins, uroporphyrins, and intermediate porphyrins (heptacarboxyl, hexacarboxyl, and pentacarboxyl).
 
Porphyrins Screen Method: Spectrophotometry by In-Common Laboratories.
 
Quantitation Method: HPLC by In-Common Laboratories.
 
For questions/information: Call Metabolic Lab at 204-787-4530 and ask for the Biochemical Geneticist.  

Patient Preparation Instructions: Healthcare provider must make arrangements with the laboratory prior to patient presenting for collection.
Collection Devices:
Preferred Device:
1 - Urine Collection Container, Random 100 mL  - Specimen must be collected at a Shared Health laboratory only.
 
Collect random urine into a 100 mL amber or light-protected container.
 
Deliver immediately the sample to the lab.
 
This collection is not suitable for ALA/PBG testing.
Specimen Required:
Pediatric Urine: 20.0 mL

Upon reception, check the pH and add a very small amount (grain of rice) of sodium carbonate as a preservative, mix well and check the pH again. Repeat if necessary. Specimen should be between 7-10. Must be added within 4 hours of collection.
 
Store refrigerated and protected from light.
 
Rejection & Stability: See More Information section below.
Referral:

Collection site: Upon reception, check the pH and add a very minute amount of sodium carbonate as a preservative, mix well and check the pH again. Repeat if necessary. Specimen should be between 7-10. Must be added within 4 hours of collection.
 
Store and ship entire specimen frozen and protected from light to the Metabolic Lab (HSC)
 
Rejection & Stability: See More Information section below.
Requisition:
Reference Values:
A descriptive report will be sent
Availability:
Within 2 Weeks
Not routinely available. Requires approval of Biochemical Geneticist prior to collection if child less than 16 years old or if unable to collect 24h specimen.
See Also:
More Information:
If you have any questions, please communicate with the Metabolic Lab (HSC): 204-787-4530
 
IMPORTANT NOTE: Strict minimum pediatric volume: 2.5 mL
Use minimum sodium carbonate to obtain a pH between 7-10. Otherwise, the sample will be rejected.
 
There is no substitution to sodium carbonate to adjust pH.
 
Reject due to: Wrong pH, not preserved with sodium carbonate, sample older than 7 days, not protected from light, not approved by Biochemical Geneticist/Clinical Chemist
 
Stability: 7 days frozen (light protected)
 
Store and ship frozen (light protected) to In-Common Laboratories.
Test ID: PORPHSR