Homocystine, Urine (Referred Out) - Saskatoon
Discipline
Biochemistry
Overview
Description
Test ordering requirements
Forms required
- Requisitions must have specific test indicated
- Miscellaneous Specimen Requisition Form #101878 or SHR Laboratory Medicine Community Laboratory Requisition Form #101064 or Acute Care Phlebotomy Requisition Form #101062
Alias
- Homocystinuria
Specimen Information
Specimen types accepted
- Random Urine
Specimen collection container
- Preferred collection container: Sterile Wide Mouthed Screw Cap Container (Pink top)
Required volume
- Optimal volume: 5 mL urine
- Minimum/pediatric volume: 1 mL urine
Transport and stability
- Send to SPH on an ice pack.
- Freeze immediately upon receipt in the lab.
- Ship frozen to referral laboratory
Rejection criteria
- If specimen thaws it is unsuitable for analysis.
- Specimens received where the proper collection protocols were not followed
- Pathology and Laboratory Medicine Acceptance and Rejection Criteria
Testing Information
Relevant clinical history
- Family History
- Relevant Recent Medication History - A recent medication list is relevant for clinical interpretation of results
Performance
Methodology
- Liquid Chromatography/Tandem Mass Spectrometry
Days/times performed
Availability |
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Testing site |
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Maximum laboratory time
- 7 day turnaround time be referral laboratory
Other information
Additional comments
This test can be used to evaluate primary and secondary disorders of methionine metabolism in conjunction with plasma amino acids and urine organic acids. Homocysteine may accumulate due to dietary vitamin B 12 deficiency and various genetic defects including methionine adenosyltransferase, glycine N-methyltransferase, adenosylhomocysteine hydrolase, methylenetetrahydrofolate reductase (MTHFR), and CBS, and enzymes involved in vitaminin B12 transport and metabolism. Homocystinuria is the most common form of these disorders, and caused by CBS deficiency.
Last Updated: October 18, 2024