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Test ID: FLT FLT3 Mutation Analysis, Varies

Useful For

A prognostic indicator in some patients with acute myeloid leukemia

 

This test should not be used to monitor residual disease following treatment.

Method Name

Polymerase Chain Reaction (PCR)/Capillary Electrophoresis

Reporting Name

FLT3 Mutation Analysis, V

Specimen Type

Varies


Advisory Information


This test is intended to be used as a prognostic test at diagnosis and should not be used to monitor residual disease following treatment.



Shipping Instructions


Specimen must arrive within 7 days of collection.



Necessary Information


The following information is required:

1. Pertinent clinical history

2. Clinical or morphologic suspicion

3. Date and time of collection

4. Specimen source



Specimen Required


Submit only 1 of the following specimens:

 

Specimen Type: Peripheral blood

Container/Tube: Lavender top (EDTA) or yellow top (ACD)

Specimen Volume: 3 mL

Collections Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube. Do not aliquot.

3. Label specimen as blood.

Specimen Stability: Ambient (preferred)/Refrigerate

 

Specimen Type: Bone marrow

Container/Tube: Lavender top (EDTA) or yellow top (ACD)

Specimen Volume: 2 mL

Collections Instructions:

1. Invert several times to mix bone marrow.

2. Send specimens in original tube. Do not aliquot.

3. Label specimen as bone marrow.

Specimen Stability: Ambient (preferred)/Refrigerate

 

Specimen Type: Extracted DNA from blood or bone marrow

Container/Tube: 1.5- to 2-mL tube

Specimen Volume: Entire specimen

Collection Instructions:

1. Label specimen as extracted DNA from blood or bone marrow

2. Indicate volume and concentration of DNA on the label.

Specimen Stability: Frozen (preferred)/Refrigerate/Ambient


Specimen Minimum Volume

Blood, Bone Marrow: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies 7 days

Clinical Information

The FMS-like tyrosine gene (FLT3) codes for a transmembrane receptor/signaling protein (FLT3) of the tyrosine kinase group. Binding of FLT3 ligand to the FLT3 receptor ultimately leads to production of proteins that cause cell growth and inhibit cell death through apoptosis. Recently, variants in FLT3 have been found in some hematopoietic neoplasms and are particularly common in adult acute myeloid leukemia (AML) with an overall incidence of approximately 20% to 30%. The highest genetic variant rates are seen in adult patients with AML and normal- or intermediate-risk cytogenetics, and patients with acute promyelocytic leukemia.

 

The most common FLT3 variant consists of internal tandem duplication (ITD) of DNA sequences found in exons 14 or 15. In some subgroups of adults with AML, the presence of an FLT3 ITD variant has been found to be an adverse prognostic indicator. The second most common variant is a point alteration in the codon for an aspartate residue (D835) that resides in the activation loop of the FLT3 protein. D835 alterations have been identified in approximately 7% of AML cases but, at this time, it is not clear if the presence of this alteration has any prognostic significance. It is thought that both types of FLT3 variants lead to constitutive (always present, independent of internal or external stimuli) FLT3 activation.

 

Identification of an FLT3 variant in AML is clinically useful, not only because of the prognostic information it provides, but also because FLT3-inhibitory drugs have shown promise as useful therapeutic agents.

Reference Values

An interpretive report will be provided.

Interpretation

An interpretive report will be issued indicating whether the FLT3 internal tandem duplication (ITD), D835 alteration, or both were detected.

 

Variant status will be indicated as positive or negative. If ITD positive, an allelic ratio will be reported.

Clinical Reference

1. Levis M, Small D: FLT3: ITDoes matter in leukemia. Leukemia. 2003 September;17:1738-1752

2. Gilliland DG, Griffin JD: The roles of FLT3 in hematopoiesis and leukemia. Blood. 2002 September 1;100(5):1532-1542

3. He R, Devine DJ, Tu ZJ, et al: Hybridization capture-based next generation sequencing reliably detects FLT3 mutations and classifies FLT3-internal tandem duplication allelic ratio in acute myeloid leukemia: a comparative study to standard fragment analysis. Mod Pathol. 2019 August 30;33:334-343

Day(s) and Time(s) Performed

Monday through Saturday

Analytic Time

3 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81245-FLT3 ITD mutation detection. CPT Code Description: FLT3 (fms-related tyrosine kinase) (eg, acute myeloid leukemia), gene analysis, internal tandem duplication (ITD) variants (ie, exons 14, 15)

81246-FLT3 (fms-related tyrosine kinase 3) (eg, acute myeloid leukemia), gene analysis; tyrosine kinase domain (TKD) variants (eg, D835, I836)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
FLT FLT3 Mutation Analysis, V 79210-1

 

Result ID Test Result Name Result LOINC Value
MP009 Specimen Type 31208-2
41935 FLT3 Result 79210-1
19236 Final Diagnosis: 34574-4

Forms

1. Hematopathology Patient Information (T676) in Special Instructions

2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.

Testing Algorithm

The following algorithms are available in Special Instructions:

-Acute Myeloid Leukemia: Testing Algorithm

-Acute Myeloid Leukemia: Relapsed with Previous Remission Testing Algorithm 

Mayo Clinic Laboratories | Hematology Catalog Additional Information:

mml-acute-leukemia