FISH, ALL, Pre-B Panel

Test Code
40052


Alias/See Also
1230400026 | LAB7564: FISH, ALL, Pre-B | QUEST EAP: 40052


CPT Codes
88271 (x9), 88275 (4)

Includes
11q (MLL), 4,10,17, t(9;22), t(12;21)


Preferred Specimen
3 mL bone marrow or 5 mL whole blood collected in a sodium heparin (green-top) tube


Minimum Volume
1 mL


Other Acceptable Specimens
Sodium heparin (royal blue-top) tube • Sodium heparin lead-free (tan-top) tube


Instructions
Clinical history and reason for referral are required with test order. Prior therapy and transplant history should be provided with test order.

Specimen viability decreases during transit. Send specimen to testing lab for viability determination. Do not freeze. Do not reject.


Transport Temperature
Room temperature


Specimen Stability
Room temperature: See instructions
Refrigerated: See instructions
Frozen: See instructions


Methodology
Fluorescence in situ Hybridization (FISH)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Sun-Fri; Report available: 7 days


Reference Range
See Laboratory Report


Clinical Significance
This panel uses fluorescence in situ hybridization (FISH) to detect common genetic abnormalities associated with B-cell acute lymphoblastic leukemia (B-ALL) and may aid in risk stratification and treatment decisions. These genetic abnormalities include the following: KMT2A (MLL) translocation, the BCR/ABL1 fusion gene resulting from the t(9;22)(q34;q11.2) translocation, the ETV6/RUNX1 (TEL/AML1) fusion gene resulting from the t(12;21)(p13;q22) translocation, and trisomy of chromosomes 4, 10, and 17.

While laboratory diagnosis of B-ALL generally requires morphologic evaluation and immunophenotyping, identifying genetic abnormalities is essential for risk stratification and patient management [1,2]. The College of American Pathologists and the American Society of Hematology recommend testing children with suspected or confirmed B-ALL for the following: trisomy 4 and 10, the BCR/ABL1 fusion gene resulting from the t(9;22)(q34;q11.2) translocation, the ETV6/RUNX1 fusion gene resulting from the t(12;21)(p13;q22) translocation, KMT2A translocation, and intrachromosomal amplification of chromosome 21 (iAMP21) [3].

A combination of genetic techniques is often involved in identifying genetic abnormalities. FISH testing is complementary to conventional cytogenetic analysis (karyotyping) and can be used to detect common cytogenetic abnormalities, especially cryptic ones not identified by karyotyping, such as the ETV6/RUNX1 fusion gene caused by t(12;21)(p13;q22) and iAMP21 (also detectable with FISH for ETV6/RUNX1) [1,2]. However, because FISH is limited to probing specific chromosomal regions, it does not replace conventional cytogenetic analysis or chromosomal microarray for screening unknown abnormalities.

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

References
1. Naresh KN, et al. B-cell lymphoid proliferations and lymphomas. In: WHO Classification of Tumours Editorial Board. The World Health Organization Classification of Haematolymphoid Tumours. 5 Beta V2 ed. IARC Press; 2022:chap 4. Accessed June 8, 2023. https://tumourclassification.iarc.who.int
2. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Acute lymphoblastic leukemia. Version 2.2023. Updated July 28, 2023. https://www.nccn.org
3. Arber DA, et al. Arch Pathol Lab Med. 2017;141(10):1342-1393.


Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153


Last Updated: April 21, 2023


The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.