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FISH, Chromosome 20q Deletion
Test Code10055
CPT Codes
88271, 88275
Includes
Note: If results are not possible, the test order may be canceled and replaced with a Cytogenetics Communication.
Preferred Specimen
3 mL bone marrow or 5 mL whole blood collected in sodium heparin (green-top) tube
Minimum Volume
1 mL bone marrow • 3 mL whole blood
Other Acceptable Specimens
Bone marrow or whole blood collected in: sodium heparin (royal blue-top) tube, or sodium heparin lead-free (tan-top) tube
Instructions
Clinical history/reason for referral is 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.
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
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: Daily; Report available: 5 days
Reference Range
See Laboratory Report
Clinical Significance
This fluorescence in situ hybridization (FISH) assay detects chromosome 20q12 deletion and may aid in the diagnosis and prognostic assessment of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML).
Deletion of chromosome 20q is a recurrent genetic abnormality associated with myeloid disorders, including MDS and AML. In the diagnosis of MDS, del(20q) is considered one of the MDS-associated karyotypes and can be used to help establish the diagnosis [1]. According to the Revised International Prognostic Scoring System (IPSS-R), del(20q) as a single anomaly in patients with MDS indicates good prognosis [2].
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. 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. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Myelodysplastic syndromes. Version 1.2023. Updated September 12,2022. https://www.nccn.org
2. Greenberg PL, et al. Blood. 2012;120(12):2454-2465.
Deletion of chromosome 20q is a recurrent genetic abnormality associated with myeloid disorders, including MDS and AML. In the diagnosis of MDS, del(20q) is considered one of the MDS-associated karyotypes and can be used to help establish the diagnosis [1]. According to the Revised International Prognostic Scoring System (IPSS-R), del(20q) as a single anomaly in patients with MDS indicates good prognosis [2].
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. 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. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Myelodysplastic syndromes. Version 1.2023. Updated September 12,2022. https://www.nccn.org
2. Greenberg PL, et al. Blood. 2012;120(12):2454-2465.
