Factor XIII V34L Mutation Analysis

Test Code

16178

CPT Codes
81400

Physician Attestation of Informed Consent

This germline genetic test requires physician attestation that patient consent has been received if ordering medical facility is located in AK, DE, FL, GA, IA, MA, MN, NV, NJ, NY, OR, SD or VT or test is performed in MA.

Preferred Specimen

5 mL whole blood collected in an EDTA (lavender-top) tube

Minimum Volume

3 mL

Other Acceptable Specimens

Whole blood collected in: ACD solution A or B (yellow-top) tube, lithium heparin (green-top) tube, or sodium heparin (green-top) tube

Instructions

Whole blood: Normal phlebotomy procedure. Specimen stability is crucial. Store and ship room temperature immediately. Do not freeze.

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 8 days
Refrigerated: 8 days
Frozen: Do not freeze

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Received frozen

Methodology
Polymerase Chain Reaction (PCR) • Single Nucleotide Primer Extension

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Thurs; Report available: 8-15 days

Reference Range

See Laboratory Report

Clinical Significance

A large meta-analysis provided evidence that the FXIII Val34Leu variant (NT_034880.3, 6258794) has a small, but significant protective effect against VTE. The variant is common in White populations, with a frequency of approximately 0.25-0.30. However, the frequency varies among ethnic groups, with the lowest (0.1) in Japanese and the highest (0.40) in Pima Indians. The biochemical consequences of the FXIII Val34Leu variant are not well understood. The FXIII Val34Leu variant does not result in a change in the plasma concentration of FXIII, but the amino acid change may modify FXIII activity. Activation of FXIIIA by thrombin was found to progress two to threefold more rapidly in plasma of FXIII Val34Leu variant carriers. This action has an effect on clot stability since the catalytic efficiency of thrombin-induced cleavage of FXIIIA alters the structure of the cross-linked fibrin such that fibrin fully crossed-linked by FXIII Val34Leu product has a finer structure with thinner fibers and smaller pores. Lateral aggregation of fibrin fibers is impaired.

The CPT Codes provided in this document 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 payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.