FISH for B Lymphoblastic Leukemia Panel Bone Marrow
Test Mnemonic
FSBLLM
CPT Codes
- 88271 - QTY (12)
- 88275 - QTY (6)
- 88291 - QTY (1)
- 88237 - QTY (1)
Includes
- FISH for BCRABL
- FISH for MLL
- FISH for t(12;21)(p13q22)
- FISH for Trisomy 4 and 10
- FISH for CRLF2M
- FISH for CRIGHM
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 2 - 3 mL | Bone marrow | EDTA (Lavender) | Ambient | Ambient |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 2 - 3 mL | Bone marrow | Sodium heparin (Green) | Ambient | Ambient |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 48 hours |
| Refrigerated | Acceptable |
| Frozen | Not acceptable |
Days Performed
4 days per week
Turnaround Time
5 - 7 days
Methodology
| Name | Description |
|---|---|
| Fluorescent In-Situ Hybridization (FISH) |
Clinical Info
The t(X;14)(p22.33;q32.33) or t(Y;14)(p11.32;q32.33) translocations, involving the CRLF2 and IGH genes, are cytogenetically-cryptic rearrangements. The CRLF2 gene is located within the pseudoautosomal region of the X and Y chromosomes. These rearrangements are associated with B-progenitor acute lymphoblastic leukemia (ALL) and Down syndrome ALL. They are present in approximately 19.8% of patients with extra copies of the X chromosome produced by high hyperdiploidy. CRLF2::IGH positive cells also have a high frequency (94%) of additional deletions which may reflect chromosomal instability. Although CRLF2::IGH is part of the BCR::ABL1-like ALL subtype, this rearrangement is not associated with it in all cases. In general, the prevalence of the CRLF2::IGH translocation increases with age.