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FLT3 Gene Mutations

Test Codes

U of M: FLT3, EPIC: LAB6928, SOFT: XFLT3

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): Blood in one Lavender-top EDTA or Yellow-top ACD tube. (Minimum: 1.0 mL)
Also acceptable: Bone marrow aspirate in one Lavender-top EDTA or Yellow-top ACD tube (Minimum: 0.5 mL) or Extracted DNA (50 ng/mcL).

Invert several times to mix blood or bone marrow.

Physician Office/Draw Specimen Preparation

Do not centrifuge. Maintain specimen in original collection tube, refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: 5.0 mL blood or 2.0 mL bone marrow, refrigerated (2-8°C or 36-46°F) in original collection tube. (Minimum: 1.0 mL blood or 0.5 mL bone marrow)

Rejection Criteria

• Frozen specimens.
• Centrifuged specimens.
• Specimens in clot or SST tubes.
• Specimens not collected and processed as indicated.

In-Lab Processing

Do not centrifuge. Maintain specimen in original collection tube, refrigerated (2-8°C or 36-46°F) prior to transport.

Transport: 5.0 mL blood or 2.0 mL bone marrow, refrigerated (2-8°C or 36-46°F) in original collection tube. (Minimum: 1.0 mL blood or 0.5 mL bone marrow) 

Storage

Specimen Stability for Testing:

Room temperature (20-26°C or 68-78.8°F): 48 hours
Refrigerated (2-8°C or 36-46°F): 48 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Sendout Laboratory with any questions.

Laboratory

Sent to the University of Michigan, Ann Arbor, MI.

Performed

Monday – Friday.
Results available in 3-8 days.

Reference Range

Negative (no mutations).

Test Methodology

Multiplex Polymerase Chain Reaction (PCR) followed by Capillary Electrophoresis.

Interpretation

This test detects the two types of mutation in the FLT3 gene, reported in cases of acute myeloid leukemias (AML) and myelodysplastic syndromes (MDS). The internal tandem duplication (ITD) mutation within the juxtamembrane region of FLT3 and the point mutation at Asp835 within the kinase domain lead to constitutively activated tyrosine kinase activity.

Clinical Utility

FLT3 gene mutations represent the most frequent gene abnormality in AML, particularly in cases with normal cytogenetics and are seen in up to 41% of all AML cases. The mutations are also seen in a subset of MDS cases (3%). The FLT3 mutations are associated with poor prognosis. Positivity for FLT3 mutations also serves as a clonal marker in AML and MDS and it is evaluated in clinical trials as a molecularly defined therapeutic target.

CPT Codes

81245, 81246.

Contacts

Last Updated

4/10/2021