|
|
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
FISH, APL, RARA-BA
Test Code16665
CPT Codes
88271 (x2), 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 a sodium heparin (green-top) tube or EDTA (lavender-top) tube
Minimum Volume
1 mL bone marrow • 3 mL whole blood
Other Acceptable Specimens
Whole blood collected in a sodium heparin (royal blue-top) or sodium heparin lead-free (tan-top) tube • Bone marrow collected in a bone marrow transport tube (available upon request), sodium heparin (royal blue-top) 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 uses a break-apart probe to detect chromosomal translocations involving the RARA gene region at chromosome 17q21. The results of this test may aid in the diagnosis of acute promyelocytic leukemia (APL) with variant RARA translocations.
APL is a subtype of acute myeloid leukemia with distinct clinical and histopathologic features. Most patients with APL harbor a translocation that involves the RARA gene on chromosome 17 and the PML gene on chromosome 15, which results in a PML/RARA fusion gene [1]. The College of American Pathologists and the American Society of Hematology recommend rapid detection of the PML/RARA fusion gene for patients with suspected APL [2]. A FISH test with dual-fusion probes can be used to detect the PML/RARA fusion gene and help establish the diagnosis. However, approximately 5% of patients with APL harbor variant RARA translocations that involve partner genes other than PML [1]. This FISH test with the RARA break-apart probe is useful for assessing the RARA status when morphology is suspicious for APL but the PML/RARA fusion gene is not detected.
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. Khoury DJ, et al. Myeloid proliferations and neoplasms. In: WHO Classification of Tumours Editorial Board. The World Health Organization Classification of Haematolymphoid Tumours. 5 Beta V2 ed. IARC Press; 2022:chap 2. Accessed June 8, 2023. https://tumourclassification.iarc.who.int
2. Arber DA, et al. Arch Pathol Lab Med. 2017;141(10):1342-1393.
APL is a subtype of acute myeloid leukemia with distinct clinical and histopathologic features. Most patients with APL harbor a translocation that involves the RARA gene on chromosome 17 and the PML gene on chromosome 15, which results in a PML/RARA fusion gene [1]. The College of American Pathologists and the American Society of Hematology recommend rapid detection of the PML/RARA fusion gene for patients with suspected APL [2]. A FISH test with dual-fusion probes can be used to detect the PML/RARA fusion gene and help establish the diagnosis. However, approximately 5% of patients with APL harbor variant RARA translocations that involve partner genes other than PML [1]. This FISH test with the RARA break-apart probe is useful for assessing the RARA status when morphology is suspicious for APL but the PML/RARA fusion gene is not detected.
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. Khoury DJ, et al. Myeloid proliferations and neoplasms. In: WHO Classification of Tumours Editorial Board. The World Health Organization Classification of Haematolymphoid Tumours. 5 Beta V2 ed. IARC Press; 2022:chap 2. Accessed June 8, 2023. https://tumourclassification.iarc.who.int
2. Arber DA, et al. Arch Pathol Lab Med. 2017;141(10):1342-1393.
