Ordering Recommendation

Preferred molecular (DNA) test to confirm a diagnosis of primary carnitine deficiency following clinical and/or biochemical presentation. To diagnose or rule out primary carnitine deficiency, refer to Carnitine, Free & Total (Includes Carnitine, Esterified) (0080068) and Carnitine, Free and Total, Urine (0081308).

Mnemonic
PCD FGA
Methodology

Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification

Performed

Varies

Reported

28-35 days

New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 2 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval
Interpretive Data

Background information for Primary Carnitine Deficiency (SLC22A5) Sequencing and Deletion/Duplication:
Characteristics: Hypoketotic hypoglycemia during periods of fasting, hepatomegaly, Reye syndrome, sudden infant death, developmental delay, cardiac and/or skeletal myopathy, hypotonia and enlarged heart.
Incidence: 1 in 40,000 for European Caucasian and Japanese, lower in other populations.
Inheritance: Autosomal recessive.
Cause: Pathogenic SLC22A5 gene mutations.
Clinical Sensitivity: May be as high as 95 percent.
Methodology: Bidirectional sequencing of the entire coding region and intron-exon boundaries of SLC22A5 gene; Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large SLC22A5 coding region deletions/duplications.
Analytical Sensitivity: Greater than 99 percent.
Limitations: Mutations in genes other than SLC22A5 will not be detected; deletion/duplication breakpoints will not be determined; deep intronic mutations and promoter mutations in the SLC22A5 gene will not be detected. Mutations within the primer/probe regions could affect the analytical sensitivity of this assay. Diagnostic errors can occur due to rare sequence variations.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

81405; 81479

Components
Component Test Code* Component Chart Name LOINC
2004204 PCD FGA Specimen
2004205 Primary Carnitine Deficiency Interpretat
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Aliases
  • Carnitine Deficiency
  • SLC22A5 sequencing and deletion/duplication assay
Primary Carnitine Deficiency (SLC22A5) Sequencing and Deletion/Duplication