Test Catalog

Test Id : KITQ

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KIT p.Asp816Val Variant Analysis, Quantitative, Varies

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

Diagnosing systemic mastocytosis

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test uses droplet digital polymerase chain reaction to detect the KIT NM_000222.3:c.2447A>T(p.Asp816Val) variant.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Method Name
A short description of the method used to perform the test

Droplet Digital Polymerase Chain Reaction (ddPCR)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

KIT D816V Variant Analysis Quant, V

Aliases
Lists additional common names for a test, as an aid in searching

c-KIT

D816V

Systemic mastocytosis

Mast cell disorder

Mastocytosis

Systemic Mast cell disease

Mast cell disease

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Specimen Type
Describes the specimen type validated for testing

Varies

Shipping Instructions

Whole blood or bone marrow specimens must arrive within 14 days of collection.

Necessary Information

Specimen type is required to perform testing.

ORDER QUESTIONS AND ANSWERS

Question ID Description Answers
MP089 Specimen Type

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix.

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

3. Label specimen as blood.

Specimen Stability Information: Ambient (preferred) 14 days/Refrigerate 14 days

 

Specimen Type: Bone marrow aspirate

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix.

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

3. Label specimen as bone marrow.

Specimen Stability Information: Ambient (preferred) 14 days/Refrigerate 14 days

 

Specimen Type: Extracted DNA

Container/Tube: 1.5- to 2-mL tube

Specimen Volume: Entire specimen

Collection Instructions:

1. Label specimen as extracted DNA

2. Provide indication of volume of DNA.

Specimen Stability Information: Frozen (preferred)/ Refrigerate/Ambient

Additional Information: We cannot guarantee that all extraction methods are compatible with this test. If testing fails, one repeat will be attempted, and if unsuccessful, the test will be reported as failed, and a charge will be applied.

 

Specimen Type: Paraffin-embedded bone marrow aspirate clot

Container/Tube: Paraffin block

Specimen Stability Information: Ambient

 

Specimen Type: Tissue (FFPE)

Container/Tube: Paraffin block

Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block.

Specimen Stability Information: Ambient

Additional Information: Decalcified core biopsies are not accepted.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

Blood, bone marrow: 1 mL; Extracted DNA: 50 mcL at 10 ng/mcL concentration; Paraffin block: 1 block

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia OK
Gross icterus Reject
Moderately to severely clotted Bone marrow core biopsies (decalcified embedded) Slides Paraffin shavings Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Varies Varies

Useful For
Suggests clinical disorders or settings where the test may be helpful

Diagnosing systemic mastocytosis

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test uses droplet digital polymerase chain reaction to detect the KIT NM_000222.3:c.2447A>T(p.Asp816Val) variant.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Systemic mastocytosis (SM) is a hematopoietic neoplasm that is now recognized as a distinct entity in the current World Health Organization and International Consensus Classifications. SM is characterized by a proliferation of neoplastic mast cells in the bone marrow and rarely in extramedullary sites. SM may present with variable degrees of clinical severity and can sometimes be associated with a non-mast cell hematologic neoplasm. SM is diagnosed using a combination of major and minor criteria, encompassing morphologic, biochemical and molecular genetic features. An important minor criterion is the presence of an activating somatic mutation in the KIT gene, encoding the tyrosine kinase receptor for stem cell factor, which is a critical growth factor in early myeloid cell proliferation and development. In SM, the most common KIT alteration is a missense change in exon 17 at codon 816, p.Asp816Val (D816V). Much less frequently, other missense mutations involving the D816 codon or adjacent amino acids are encountered and rarely, KIT genetic alterations can occur in other exons. A subset of acute myeloid leukemias (AML) with core-binding factor gene fusions can also acquire activating KIT gene mutations, including D816V in many cases. Detection of KIT D816V is critical to help establish a diagnosis of SM and is optimally determined by molecular testing. Because mast cell lesions are typically sparse and fibrotic in bone marrow and circulating tumor mast cells are in low abundance, highly sensitive and specific assays are required for optimal detection of KIT D816V. This can be achieved using quantitative allele-specific polymerase chain reaction (PCR) or droplet digital PCR (ddPCR) methods. The presence of KIT D816V mutation in the appropriate clinical and pathologic context is highly supportive of SM. In addition, although the D816V in SM is insensitive to targeted therapy with imatinib, other tyrosine kinase inhibitors such as avapritinib have demonstrated significant therapeutic efficacy in advanced SM, indicating that this mutation may also be a theranostic marker for these patients.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided indicating the status as positive or negative for KIT p.Asp816Val (D816V).

KIT gene (NCBI accession NM_000222.3)

Interpretation
Provides information to assist in interpretation of the test results

The test will be interpreted as positive or negative for KIT p.Asp816Val and a quantitative result will be included if positive.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Some cases of systemic mastocytosis (SM)  may have sparse representation in bone marrow aspirate or blood samples containing too few neoplastic mast cells to successfully detect the KIT p.D816V (below limit of assay detection). Paraffin embedded tissues may be prone to sampling effects and DNA degradation, which may also compromise assay performance. Rare cases of SM may have other KIT mutations involving D816 (such as p.D816Y), or in other exon 17 codons that are not specifically targeted by this D816V ddPCR assay.

 

Assay sensitivity may be impacted by variability in tumor cell distribution or limited overall DNA quantity or quality.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Khoury JD, Solary E, Abla O, et al. The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Myeloid and Histiocytic/Dendritic Neoplasms. Leukemia. 2022;36(7):1703-1719

2. Arber DA, Orazi A, Hasserjian RP, et al. International Consensus Classification of Myeloid Neoplasms and Acute Leukemias: integrating morphologic, clinical, and genomic data. Blood. 2022;140(11):1200-1228

3. Reiter A, George TI, Gotlib J. New developments in diagnosis, prognostication, and treatment of advanced systemic mastocytosis. Blood. 2020;135(16):1365-1376

4. Arock M, Sotlar K, Broesby-Olsen S, et al. KIT mutation analysis in mast cell neoplasms: recommendations of the European Competence Network on Mastocytosis. Leukemia. 2015;29:1223-1232

5. Valent P, Akin C, Metcalfe DD. Mastocytosis: 2016 updated WHO classification and novel emerging treatment concepts. Blood. 2017;129(11):1420-1427

6. Munoz-Gonzalez JI, Alvarez-Twose I, Jara-Acevedo M, et al. Frequency and prognostic impact of KIT and other genetic variants in indolent systemic mastocytosis. Blood. 2019;134(5):456-468

7. Gotlib J, Reiter A, DeAngelo DJ. Avapritinib for advanced systemic mastocytosis. Blood. 2022;140(15):1667-1673

Method Description
Describes how the test is performed and provides a method-specific reference

This test is performed using droplet digital polymerase chain reaction (ddPCR) to detect the KIT:c.2447A>T, p.Asp816Val (NM_000222.3:g.55599321A>T) variant. DNA extracted from patient samples is PCR-amplified using oligonucleotide primers and mutant- and wild type-specific fluorescently labeled probes. Results are analyzed using dedicated software and Poisson statistics to provide absolute quantification of mutant target and wild type copies. Calculated results are reported as KIT p.D816V mutant fractional abundance (variant allele fraction %). The analytical sensitivity of this assay is 0.1%; however, sensitivity may be impacted by variability in tumor cell distribution or limited overall DNA quantity or quality.(Unpublished Mayo method)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

4 to 7 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

Whole blood/Bone marrow: 2 weeks; Extracted DNA: 3 Months; Paraffin blocks: Unused portions of blocks will be returned 1 week after testing is complete

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

81273

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
KITQ KIT D816V Variant Analysis Quant, V 55201-8
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
MP089 Specimen Type 31208-2
622375 Interpretation 69047-9
622376 Signing Pathologist 19139-5

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports

Test Update Resources

Change Type Effective Date
New Test 2025-03-04