TK2 DNA Sequencing Test (related to mtDNA depletion)

Test Code

Test Details

Test code: 489
Type of disorder: Mitochondrial Disorders
Disease(s) tested for: Mitochondrial Disease associated with Mitochondrial Depletion Syndrome
Genes Included: TK2
Profiles that contain this test:
Informed Consent Required: This test requires physician attestation that patient consent has been received

Technical Information

Clinical Significance: Identifies mutations in the TK2 gene related to mitochondrial DNA depletion

Typical Presentation: Mitochondrial disease is a clinically heterogeneous group of multisystem disorders characterized by muscle weakness and wasting caused by mutations of nuclear or mitochondrial DNA. TK2 is associated with a hepatoencephalopathic form of mitochondrial disease.

Indications for testing: Symptomatic individuals consistent with hepatoencephalopathic forms of mitochondial disease.
Methodology: Sanger Sequencing
Reference Range: No mutations detected

CPT Coding

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

CPT: 81405(1)

Specimen Requirements

Please label each specimen tube with two forms of patient identification. These forms of identification must also appear on the requisition form.

Specimen Type: Whole blood
Specimen Stability: Room temperature: 10 days, Refrigerated: 10 days, Frozen: Unacceptable
Specimen Requirements: 8 mL (6 mL minimum) whole blood collected in two (lavender-top) EDTA tubes. Pediatric (0-3 years): 2 mL (1 mL minimum)
Instructions: Higher blood volumes ensure adequate DNA quantity, which varies with WBC, specimen condition, and need for confirmatory testing. Patients, 0-3 years have higher WBC, yielding more DNA per mL of blood

Shipping Considerations

Transport Temperature: Room temperature
Set-up/Analytic Time: 14-28 days

Additional Resources

Letters of Medical Necessity

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