FLT3 Mutation Analysis

CPT: 81245; 81246
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Synonyms

  • FLT3 D835 mutation
  • FLT3 Internal Tandem Duplication and Tyrosine Kinase Domain mutation
  • FLT3 ITD and D835 mutations
  • FLT3 ITD and TKD mutations
  • FLT3 ITD mutation
  • FLT3 TKD mutation

Special Instructions

Please direct any questions regarding this test to customer service at 800-345-4363.




Specimen Requirements


Specimen

Whole blood, bone marrow or cell pellet


Volume

3-5 mL whole blood or 1-2 mL bone marrow


Minimum Volume

3 mL whole blood or 1 mL bone marrow


Container

Lavender-top (EDTA) tube or green-top (sodium heparin) tube


Collection

Ship specimen at room temperature. Specimen should arrive in the laboratory within 48 hours of collection. Indicate date and time of collection on the request form.


Storage Instructions

Refrigerate. If specimen is to be stored prior to shipment, store at 2°C to 8°C.


Causes for Rejection

Specimen does not meet collection criteria; frozen whole blood, marrow, or cell pellet; leaking tube; clotted blood or marrow; grossly hemolyzed specimen or otherwise visibly degraded; contamination by another specimen; specimens containing suspicious foreign material


Test Details


Use

Mutations in the FLT3 gene are common mutations in acute myeloid leukemia (AML). This assay detects internal tandem duplication (ITD) mutations and mutations in the tyrosine kinase domain (TKD) of FLT3. Presence of these mutations in AML provide prognostic information and can aid in the determination of therapeutic regimen.


Limitations

This PCR assay is capable of detecting a mutant cell population with a sensitivity of 5 mutant cells per 100.

This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.


Methodology

Polymerase chain reaction (PCR); restriction enzyme digest; capillary electrophoresis


Additional Information

FLT3 is a receptor tyrosine kinase (RTK) that dimerizes on binding its ligand, the cytokine FLT3 ligand (FL), which then undergoes autophosphorylation, and transduces signals downstream (STAT, AKT, ERK) that promote proliferation and survival. Activating mutations of FLT3 are common mutations found in AML. A particular form of FLT3 is mutated by duplicating coding sequence derived from the juxtamenbrane domain inserted in tandem (internal tandem duplication (ITD). These FLT3-ITD mutations result in the constitutive activation of the tyrosine kinase function. Patients with FLT3-ITD mutations have increased relapse rates and reduced overall survival. Point mutations in the activation loop of the kinase domain, most commonly at the residue Asp 835 (D835), also known as tyrosine kinase domain (TKD) mutations, also result in the constitutive activation of the FLT3 kinase. Signaling from FLT3-TKD mutations does not appear as abnormal, and the prognostic impact appears to be less severe when compared with ITD mutations (FLT3-ITD mutations are found in ~23% of AML cases, whereas TKD mutations are found in 7%). Recently the FDA approved a new combination treatment of AML that is FLT3 mutation positive. The kinase inhibitor RYDAPT® (midostaurin), in combination with chemotherapy was approved as the first targeted therapy for AML.


References

Levis, M. Midostaurin approved for FLT3-mutated AML. Blood. 2017 Jun 29;129(26):3403-3406.28546144
National Comprehensive Cancer Network. NCCN Guidelines Version 3.2018 - Acute Myeloid Leukemia. National Comprehensive Cancer Network, Plymouth Reading, PA; 2018.
Pratz KW, Levis M. How I treat FLT3-mutated AML. Blood. 2017 Feb 2;129(5):565-571.27872057

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
485010 FLT3 Mutation Analysis 485012 FLT3 ITD Result 79210-1
485010 FLT3 Mutation Analysis 485019 FLT3 D835 Result 72520-0
485010 FLT3 Mutation Analysis 485013 Background 77202-0
485010 FLT3 Mutation Analysis 485015 Method 49549-9
485010 FLT3 Mutation Analysis 485016 References 75608-0
485010 FLT3 Mutation Analysis 485017 Director Review 72486-4

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