Acylcarnitine, Urine (Referred Out) - Saskatoon

Overview

Description

Ordering Recommendation

• If clinically feasible, discontinue L-carnitine supplementation at least 72 hours before specimen collection

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

Specimen Information

Specimen types accepted

• Random urine

Specimen collection container

• Preferred collection container: Sterile Wide Mouth Screw Cap Container (Pink Top)

Required volume

• Optimal volume: 5 mL urine
• Minimum volume/pediatric volume: 1 mL urine

(Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection)

Transport and stability

• Freeze immediately upon receipt in the lab
• Send to SPH on an ice pack
• Store and ship frozen to referral laboratory
• Stable 24 hours when refrigerated, 7 days when frozen

Rejection criteria

• 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
• Must include diagnosis and/or patient symptoms on the requisition

Relevant Recent Medication History 

• A recent medication list is relevant for clinical interpretation of results

Clinical interpretation

• Almost all patients with isobutyryl-CoA dehydrogenase deficiency excrete an abnormal amount of iso-/butyrylcarnitine (C4) in their urine. Some, but not all, affected individuals also excrete elevated levels of isobutyrylglycine. Conversely, patients with short-chain acyl-CoA dehydrogenase deficiency can have a normal excretion of C4.

• Result interpretation should be correlated with clinical and other laboratory findings.

• If patient is receiving L-carnitine supplementation, the result of this urine acylcarnitine test will not be informative.

Performance

Methodology

• Flow injection Analysis-Tandem Mass Spectrometry (FIA-MS/MS)

Days/times performed

Availability	Shipped Weekly
Testing Site	Referred out by St. Paul’s Hospital Laboratory to Mayo Medical Laboratories

Maximum laboratory time

Results Reporting

• 5 day turnaround time by referral laboratory

Last Updated: January 7, 2026