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HelpTest Code BARQ BCR::ABL1, Rare Fusion Monitoring, Quantitative, Varies
Ordering Guidance
This test should not be used to screen for BCR::ABL1 fusions at the time of diagnosis. For diagnostic evaluation, please order BADX / BCR/ABL1, Qualitative, Diagnostic Assay, Varies; or BCRFX / BCR/ABL1 Qualitative Diagnostic Assay with Reflex to BCR/ABL1 p190 Quantitative Assay or p210 Quantitative Assay, Varies.
For measurable residual disease (MRD) monitoring of patients with chronic myeloid leukemia (CML) or, less commonly, B-cell acute lymphoblastic leukemia (B-ALL) or acute myeloid leukemia (AML) with a previously identified p210 (e13/e14-a2) fusion transcript, order BCRAB / BCR/ABL1, p210, mRNA Detection, Reverse Transcription-PCR (RT-PCR), Quantitative, Monitoring Chronic Myelogenous Leukemia (CML), Varies.
For MRD monitoring of B-ALL or rare CML or AML patients with a previously identified p190 (e1-a2) fusion transcript, order BA190 test / BCR/ABL1, p190, mRNA Detection, Reverse Transcription-PCR (RT-PCR), Quantitative, Monitoring Assay, Varies.
For more information, see BCR/ABL1 Ordering Guide for Blood and Bone Marrow
Shipping Instructions
Ambient specimens must arrive within 3 days (72 hours) of collection. Refrigerated specimens must arrive within 5 days of collection. Collect and package specimens as close to shipping time as possible.
Necessary Information
The following information is required:
1. Pertinent clinical history including if the patient has a diagnosis of chronic myeloid leukemia, B-cell acute lymphoblastic leukemia, or other BCR::ABL1-positive neoplasm
2. Specific fusion transcript if previously determined
3. Date of collection
4. Specimen source (blood or bone marrow)
Specimen Required
Submit only 1 of the following specimens:
Specimen Type: Whole blood
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Yellow top (ACD)
Specimen Volume: 10 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
3. Label specimen as blood.
Specimen Type: Bone marrow
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Yellow top (ACD)
Specimen Volume: 4 mL
Collection Instructions:
1. Invert several times to mix bone marrow.
2. Send bone marrow specimen in original tube. Do not aliquot.
3. Label specimen as bone marrow.
Forms
1. Hematopathology Patient Information (T676)
2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.
Useful For
Quantitative monitoring of rare (non-p210 [non-E13/E14A2], non-p190 [non-E1A2]) BCR::ABL1 fusion transcript types occurring in myeloid neoplasms (eg, CML, myeloproliferative neoplasms) or B-cell acute lymphoblastic leukemias.
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| BADX | BCR/ABL1, RNA-Qual, Diagnostic | Yes | No |
| BA190 | BCR/ABL1, p190, Quant, Monitor | Yes | No |
| BCRAB | BCR/ABL1, p210, Quant, Monitor | Yes | No |
Testing Algorithm
If a previous BCR::ABL1 rare fusion has not been identified by Mayo Clinic Laboratories (MCL), the qualitative, diagnostic assay for BCR::ABL1 will be performed at an additional charge to identify the fusion form.
If MCL has previously identified a p190 or p210 BCR::ABL1 fusion form, the appropriate quantitative testing will be performed and this test will be canceled.
Method Name
Droplet Digital Polymerase Chain Reaction (ddPCR)
Reporting Name
BCR::ABL1 Rare fusion Quant MonitorSpecimen Type
VariesSpecimen Minimum Volume
Whole blood: 8 mL; Bone marrow: 2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Refrigerated (preferred) | 5 days | PURPLE OR PINK TOP/EDTA |
| Ambient | 72 hours | PURPLE OR PINK TOP/EDTA |
Reject Due To
| Gross hemolysis | Reject |
| Moderately or severely clotted | Reject |
Clinical Information
The t(9;22)/BCR::ABL1 abnormality is associated with chronic myeloid leukemia (CML) and "Philadelphia-positive" acute lymphoblastic leukemia of B-cell lineage (Ph+ B-ALL). Very rarely has this abnormality also been identified in cases of acute myeloid leukemia and T-lymphoblastic leukemia/lymphoma. The fusion genes on the derivative chromosome 22q11 produce a chimeric BCR::ABL1 messenger RNA (mRNA) transcript and corresponding translated oncoprotein. Because of substantial breakpoint heterogeneity at the genomic level, BCR::ABL1 mRNA transcripts are utilized for sensitive detection and quantification by reverse transcription-polymerase chain reaction (RT-PCR) techniques. Common BCR::ABL1 fusion transcript types include the p210 (E13/E14A2) product, which is associated with nearly all cases of CML and some cases of B-ALL, and the p190 (E1A2) product, which is associated primarily with B-ALL. However, rare alternate breaks in both BCR and ABL1 are described in CML, B-ALL and other rare myeloid neoplasms, resulting in a variety of alternate BCR::ABL1 fusion transcript types. These include, but are not limited to, the p230 (E19A2) fusion, BCR::ABL1 fusions involving ABL1 A3, and other rare types (eg, E6A2, E8A2). These alternate BCR::ABL1 fusion transcript types can be identified with a comprehensive diagnostic RT-PCR screening assay (see test ID: BCRFX / BCR/ABL1 Qualitative Diagnostic Assay with Reflex to BCR/ABL1 p190 Quantitative Assay or BCR/ABL1 p210 Quantitative Assay, Varies or BADX / BCR/ABL1, Qualitative, Diagnostic Assay, Varies); however, rare transcript targets cannot be monitored using specific quantitative assays that typically target the more common p210 or p190 events. To meet this need, this test was developed using a droplet digital PCR methodology (ddPCR). If a rare BCR::ABL1 fusion type is identified by diagnostic RT-PCR screening, this test can subsequently be used to monitor patients with the specific rare fusion form. This assay provides quantitative evaluation of 10 alternate rare BCR::ABL1 fusion transcripts and better individualizes treatment response monitoring and clinical management for these patients.
Reference Values
An interpretive report will be provided
Interpretation
An interpretative report will be provided.
Cautions
Although this quantitative droplet digital polymerase chain reaction (ddPCR) assay is comprehensive for detecting and quantifying 10 rare alternative (non-p210, non-p190) BCR::ABL1 fusions, there are additional extremely rare fusions (eg, complex translocation/rearrangement events) that may produce highly unusual BCR::ABL1 products that may not be detectable by this assay
The precision of this assay at very low BCR::ABL1 levels is less reliable, such that inter-run results can be slightly variable. Significant changes during monitoring should be verified by testing a subsequent specimen.
Results of this assay cannot be directly compared with data generated from other polymerase chain reaction (PCR) assays, including similar assays performed in other laboratories.
The results of this assay cannot be directly compared with BCR::ABL1 results obtained using fluorescence in situ hybridization (FISH) technology. FISH measures the presence of rearrangements in single cells, whereas this ddPCR-based assay measures relative expression of messenger RNA (mRNA) transcripts. FISH is generally not as sensitive as ddPCR.
Blood or bone marrow can be used for disease monitoring. While BCR::ABL1 levels in blood and bone marrow drawn at the same time are generally similar, bone marrow may provide a slight increase in detection sensitivity (0.5-1 log).
Specimens with delayed transport or nearing the stability window as stated may result in sufficient RNA degradation to produce false-negative results. Thus, specimens should be shipped as quickly as possible. Ambient specimens over 3 days old and refrigerated specimens over 5 days old at the time of receipt are not acceptable.
Day(s) Performed
Weekly
Report Available
10 to 15 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
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
81208
BADX: 81206, 81207, 81208 (if appropriate)
BA190: 81207 (if appropriate)
BCRAB: 81206 (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| BARQ | BCR::ABL1 Rare fusion Quant Monitor | 75892-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| MP097 | Specimen Type | 31208-2 |
| MP098 | BCRABL Fusion | 75892-0 |
| 623494 | Signing Pathologist | 18771-6 |
| 623479 | Interpretation | 69047-9 |
Method Description
RNA is extracted from the blood or bone marrow specimen and reverse-transcribed to complementary DNA (cDNA). The cDNA template is amplified in a droplet digital PCR (ddPCR) platform using primers and fluorescent probes targeting specific BCR and ABL1 exon regions. Results are expressed quantitatively as BCR::ABL1 target transcript copies to control gene (ABL1) transcript copies. The analytical sensitivity of the assay is 0.1% BCR::ABL1/ABL1.(Lee SJ, Lee JM, Ahn A, et al. Analytical performance evaluation of a digital real-time PCR for quantifying major BCR::ABL1 transcripts. J Clin Lab Anal. 2024;38(7):e25034. doi10.1002/jcla.25034; Kockerols C, Valk PJM, Hogenbirk P, Cornelissen JJ, Westerweel PE. BCR::ABL1 deep molecular response quantification and transcript type identification in chronic myeloid leukemia using a US Food and Drug Administration-approved droplet-based digital PCR assay. J Mol Diagn. 2025;27(2):109-118. doi:10.1016/j.jmoldx.2024.11.003)