Ordering Recommendation

Appropriate initial test for Li-Fraumeni  syndrome (LFS). Should not be used to detect somatic TP53 variants associated with malignancy. Not recommended for patients with a hematologic malignancy and/or who have undergone allogeneic stem cell transplantation.

Mnemonic
TP53 FGS
Methodology

Polymerase Chain Reaction/Sequencing

Performed

Varies

Reported

21-28 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Lavender (K2EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 1 week; Refrigerated: 1 month; Frozen: 6 months

Reference Interval

By report

Interpretive Data

Background Information for Li-Fraumeni (TP53) Sequencing:
Characteristics:
  Predisposition for developing early-onset and multiple primary cancers, particularly soft tissue and bone sarcomas, adrenocortical carcinoma, brain tumors, premenopausal breast cancer, and other malignancies.
Prevalence:
1 in 5,000 - 1 in 20,000.
Inheritance:
Autosomal dominant.
Penetrance:
  Approximately 50 percent by age 30 years and 90 percent by age 60 years.
Cause:
Pathogenic germline mutations in the TP53 gene.
Clinical Sensitivity:
Approximately 80 percent for individuals meeting classic Li-Fraumeni syndrome (LFS) criteria.
Methodology:
Bidirectional sequencing of all coding regions and intron-exon boundaries of the TP53 gene.
Analytical Sensitivity and Specificity:
Greater than 95 percent.
Limitations:
 TP53 gene regulatory region mutations, deep intronic mutations, and large deletions/duplications will not be detected. Diagnostic errors can occur due to rare sequence variations. This assay is not designed to detect somatic variants associated with malignancy. Interpretation of this test result may be impacted if the patient has had an allogeneic stem cell transplantation.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

81405

Components
Component Test Code* Component Chart Name LOINC
2009303 Li-Fraumeni (TP53) Sequencing Specimen
2009304 Li-Fraumeni (TP53) Sequencing Interp
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Aliases
Li-Fraumeni (TP53) Sequencing