Days Set Up
Monday - Thursday
Analytic Time

3 - 10 days

MiChart Code
KIT Mutation - Exons 9, 11, 13, 17
Soft Order Code
GISTS

Test Updated:

Synonyms

KIT Mutation for GIST
MLABEL
GISTS
GIST
KIT Mutation Detection - GIST
KIT Mutation Detection for Gastrointestinal Stromal Tumor
KIT Mutation Detection for Imatinib Therapy
c-KIT Mutation
KIT Exon 9, 11, 13, 17 Mutations

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Test Overview

Test Methodology

Polymerase Chain Reaction (PCR) followed by sequencing analysis.

Test Usage

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. Most GISTs characteristically express the KIT receptor tyrosine kinase, and approximately 80% harbor oncogenic mutations within the KIT gene. These primarily involve KIT exon 11, but may also occur in exons 9, 13, and 17. All mutations result in the constitutive activation of KIT, which has led to the use of tyrosine kinase inhibitor drugs (imatinib) as a common therapy for GIST patients. Testing for KIT mutation can aid in the diagnosis of GIST, particularly for tumors that lack KIT expression by immunohistochemistry. Mutation testing may also aid in determining prognosis, and may help predict response to imatinib therapy, both of which have been associated with specific KIT mutations. This DNA sequencing test will detect mutations within exons 9, 11, 13, and 17 of the KIT gene. The tested exons correspond to KIT amino acids 497-513 (exon 9), 550-591 (exon 11), 628-661 (exon 13), and 799-823 (exon 17). Appropriate specimens include formalin fixed paraffin embedded tissue blocks and fresh/frozen tissues. Specimens should contain an adequate proportion of tumor nuclei (>40%) to enable mutation detection.

Reference Range

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Onsite

For formalin-fixed, paraffin-embedded tissue, a block containing an area with a high percentage of neoplastic cells (for micro-/macro-dissection) is preferred. Unstained, UNBAKED slides (5-8, 10-micron slides; 10-15 if few neoplastic cells are present) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature. Store at room temperature.

Collection Offsite

For formalin-fixed, paraffin-embedded tissue, a block containing an area with a high percentage of neoplastic cells (for micro-/macro-dissection) is preferred. Unstained, UNBAKED slides (5-8, 10-micron slides; 10-15 if few neoplastic cells are present) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature. Store at room temperature.

Normal Volume
Formalin-fixed, paraffin-embedded tissue; Diff-Quik stained aspirate smear. Extracted DNA is also acceptable if extracted in a CLIA certified laboratory.
Minimum Volume
 

Billing Information

CPT Code
81272, 88381-TC
Pro Fee Code
81404
LOINC
 

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.