Alberta Precision Laboratories

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Organization:

Alberta Precision Laboratories

Message Alert:

PLEASE NOTE: This Test Directory is in an interim state and due to changes pertaining to the DynaLIFE transition, performing site for routing has not been updated. Please refer to Laboratory Information System for appropriate routing.

Test Name/Synonym:

Carnitine, Total and Free, Blood (Synonyms: L-Carnitine Monitoring, Carnitine Deficiency, Carnitine Uptake Defect)

Clinical Indications:

This test is for the investigation of a systemic carnitine deficiency due to an underlying primary (i.e., carnitine uptake defect due to OCTN2 deficiency) or secondary (e.g., MCAD deficiency, organic acidurias, cystinosis) cause.

This test can also be used to evaluate the potential of a secondary carnitine deficiency due to nutritional inadequacy (e.g., vegan diet, total parenteral nutrition), increased metabolic demand (e.g., ketogenic diet), reduced intestinal absorption (e.g., short bowel syndrome) or increased loss (e.g., Fanconi syndrome, hemodialysis).

This test can also be used to monitor known metabolic patients on carnitine supplementation therapy.

Test Includes:

Metabolites reported: Total, Free and Acyl Carnitine

Collection Alert:

Hours fasting must be indicated. Recommend collection following a minimum four hour fast or just before next feeding for newborns.
Specimens collected from non-fasting patients will be accepted for testing.

LABID (Connect Care):

LAB815

Test Code:

CALGARY ZONE	BGLBL; IN BGL TEST NAME FIELD ENTER CARNITINE
CENTRAL ZONE SOUTH ZONE (LETHBRIDGE)	CAR
NORTH ZONE SOUTH ZONE (MEDICINE HAT)	CARG

Specimen Type:

Blood

Primary Container:

Green top – Sodium Heparin (no gel)

Alternate Containers:

Green top – Lithium heparin (no gel)
Red top – Non-additive (no gel)

Minimum Collection Volume:

Biochemical Genetics North	Biochemical Genetics South
0.5 mL plasma or serum	0.25 mL plasma or serum

Specimen Collection Requirements:

Collect one Sodium Heparin (or alternate) tube.
Indicate length of fast, or time of last feeding on the requisition (with collection time).

Test Resources:

Submit request using the applicable requisition or Connect Care online order entry:

Biochemical Genetics Laboratory Requisition

Please ensure all required information, including patient's clinical history/indication, is provided on the requisition.

Stability and Storage:

Frozen: plasma or serum aliquot

Processing:

For ALL collection locations except for Alberta Children’s Hospital (ACH):
1. Centrifuge; If red top tube is collected, allow to fully clot prior to centrifugation.
2. Transfer plasma or serum to aliquot tube.
3. Write "NaHep", "LiHep" or "Red Top" on the aliquot tube label.
4. Freeze aliquot tube.

If collected at ACH outpatient Lab:

The primary tube can be put on ice (ensure not to freeze sample) or refrigerated for routine pick-ups between 08:30 to 14:30, Monday through Friday (excluding holidays).
If specimen is collected after 14:30, process sample as described above.

Transportation:

Transport frozen specimens on dry ice.
Samples must not thaw during transport.

Method:

Liquid chromatography tandem mass spectrometry (LC-MS/MS)

Method and Interpretation of Results:

Total and free carnitine levels are measured with and without alkaline hydrolysis, and the acylcarnitine fraction calculated, using Liquid Chromatography, Electrospray-Ionization Tandem Mass Spectrometry (LC-MS/MS) with a deuterium-labelled internal standard.

Determination of plasma or serum total and free carnitine levels, with calculated acylcarnitine fraction, enables the identification of a systemic carnitine deficiency (i.e., significantly low total and free carnitine levels with or without low acylcarnitine fraction, depending on the underlying cause). Other alterations of total, free and/or acyl component measures of the test can be influenced by a patient’s underlying pathology, nutritional status as well as the application of carnitine supplementation therapy, and therefore such information should be provided on the requisition. Follow up testing of abnormal results may include recommendations for evaluation of the patient’s nutritional status, dietary predilections, current treatment and/or assessment of renal function.

This test may be reflexively performed on a sample in which a result from Acylcarnitine Profile is suggestive of low free carnitine (a metabolite monitored but not reported by that test).

Acylcarnitine Profile testing may be reflexibvely performed based on evidence of unexplained increased acylcarnitine accumulation.

Routine Turn Around Time:

14 days

Testing Schedule:

Weekly

Reference Interval:

Reference Intervals are age-dependent and will be provided on the report.

Testing Area:

Biochemical Genetics

Performing Site:

University of Alberta Hospital or Alberta Children’s Hospital

Additional Test Information:

For priority turn-around contact the appropriate Biochemical Genetics Laboratory.

Contact Comments:

Newborn Screening & Biochemical Genetics North	Biochemical Genetics South
780-407-8820	403-955-7379

Last Updated On:

Tuesday, December 20, 2022

Date of Last Review:

Aug 1 2022 12:00AM