FLT3 Mutation Detection : 1002094

Message
Indications for testing:
Stratifying high and low risk AML
At initial diagnosis of AML, ALL and MDS
Recurrence of leukemia after induction therapy on patients not initially screened for FLT3 mutations.

Test Code
FLT3PC or 1002094

Alias/See Also
TKD FLT3; ITD FLT3

CPT Codes
0023U

Instructions
Whole blood or bone marrow in a lavender (EDTA), yellow (ACD solution A or B), or green (no gel) (sodium heparin). Alternative specimens: Cell Pellets in cell culture media or buffered solutions without fixatives. 1 ug of previously isolated DNA.

Transport Container
Transport 5 mL whole blood or 3 mL bone marrow or alternative specimen types.

Transport Temperature
Refrigerated.

Specimen Stability
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Isolated DNA: 72 hours; Refrigerated: Indefinitely; Frozen: Unacceptable

Methodology
Qualitative Polymerase Chain Reaction/Capillary Electrophoresis

Setup Schedule
Monday - Saturday

Report Available
3-7 days (From receipt at performing laboratory)

Limitations
FLT3 Mutation Testing is performed pursuant to patents licensed from Takara Bio of Otsu, Japan.

Reference Range
By report.

Clinical Significance
Acute myeloid leukemia (AML) has in general a poorprognosis. Recent studies have described mutation of the FMS related tyrosine kinase 3 (FLT3) gene to be an importantprognostic factor in AML, with FLT3 mutants having a worse outcome and response to standard chemotherapeutic interventions. FLT3 is one of the most commonly mutated genes in AML, occurring in approximately 30% of patients atthe time of diagnosis. The highest mutation rates are seen in adult patients with AML and normal- or intermediate risk cytogenetics, and patients with acute promyelocytic leukemia.

The most prevalent and clinically significant type of FLT3 mutation is an internal tandem duplication (ITD) in the juxtamembrane domain. Many clinical studies have found that FLT3 ITD mutations are associated with higher concentrations of leukemic cells in both blood and bone marrow, increased incidence of relapse and decreased overall survival.

The second most common mutation type in the FLT3 gene is a tyrosine kinase domain (TKD) point mutation in the codon for an aspartate (D835) or an isoleucine (I836) residue. TKD mutations result in constitutive autophosphorylation and activation of FLT3 and have also been linked to poor overall survival, but to a lesser extent as compared to ITD mutations.

To determine the best treatment options for AML patients, it is recommended that patients with AML be screened for the presence of FLT3 mutations before induction therapy. Induction therapy is unlikely to be altered due to FLT3 mutation status; however, knowing the FLT3 mutation status can help stratify patients into groups that will receive different post-remission treatments. Currently there are several small molecule inhibitors of FLT3 in clinical trials. Identifying patients with FLT3 mutations may make patients eligible for these research therapies.

Performing Laboratory
LabPMM



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.