BCR/ABL1 Gene Rearrangement, Quantitative, PCR

Overview

  • EPIC Code:
  • LAB2879
  • Soft Test Code:
  • BCRP
  • Send Out Test Code:
  • 91065
Included Tests

If P190 transcript expression was previously documented, only P190 BCR-ABL1 will be performed at an additional charge (CPT code: 81207).  If P210 transcript expressoin was previously documented, only P210 BCR-ABL1 will be performed at an additional charge (CPT code: 81206).  If no prior positive is documented P190 BCR-ABL1 and P210 BCR-ABL1 will be performed at an additional charge (CPT Code(s): 81206, 81207)


Clinical Significance

The Philadelphia chromosome (Ph) is a translocation between chromosome 9 and 22 t(9;22) (q34;Q11) that is found in more than 90-95% of chronic myeloid leukemia (CML), and in 20-25% of adult and 2-10% of childhood acute lymphoblastic leukemia (ALL).  In CML, most translocations fall in the major breakpoint cluster region of the CBR gene, and result in either of two BCR-ABL1 mRNA molecules having an e13a2 junction (fusion of BCR exon 14 with ABL1 exon 2)  that encodes the p210 BCR-ABL1 fusion protein.  In all, about two thirds of the BCR breakpoints fall in the minor breakpoint cluster region of the BCR gene, and the hybrid BCR-ABL1 transcript contains an e1a2 junction (fusion of BCR exon 1 with AB11 exon2) which is translated as a p190 BCR-ABL1 fusion protein.  Quantitative measurement of the changes of BCR-AB1 expression levels over time is important to monitor disease progression and response to targeted therapies.  This test is a reverse-transcription pcr-based quantitative assay which detectes these two major BCR-AB11 mRNA transcripts produced by the t(9;22) chromosomal translocation (p210 and p190).  BCR-ABL1 transcript levels are expressed as a percent ratio of BCR-ABL1 to the normalizing ABL1 transcript levels.  For the p210 transcript associated with CML, quantitation is further adjusted to the international scare (IS) to allow comparison with other IS-complian BCR-ABL1 assays.  Optimal therapy in CML is associated wiht transcript levels below the major molecular response (MMR) milestone indicated by a CBR-ABL1/ABL1% (is) below 0.1.


Specimen Collection & Preparation

Specimen Requirements

5 mL whole blood or 3 mL bone marrow aspirate collected in EDTA (lavender-top) tube


Alternate Specimen

 Whole blood or bone marrow aspirate collected in sodium heparin (green-top) tube.

or 3 mL bone marrow aspirate collected in EDTA (lavender-top) tube


TransportAndStorage

 Transport ambient.
Specimen stability:  ambient 72 hours, refrigerated 72 hours, frozen unacceptable


Collection Instructions

 Do not reject specimens, send to laboratory for screening.  Collect 5 mL of whole blood or 3 mL bone marrow in an EDTA tube.  Whole blood or bone marrow is shipped at room temperature or refrigerated.  Do not freeze whole blood or bone marrow.  After collection of the sample, draw date and time, as well as sample type, must be written on the tube and included as requested information.  Ship sample immediately, due to short stability of 72 hours.  If the stability of the sample cannot be determined, delay in result or cancellation of test may occur.


Minimum Volume

3 mL whole blood or 1 mL bone marrow aspirate


Neonatal Volumne

Clinical Interpretation

Reference Range:

 BCR-ABL1/ABL1 %  0.00; BCR-ABL1/ABL1 %  (IS) 0.00; Interpretation- See Laboratory Report


Methodology:
  • Quantitative Real-Time Polymerase Chain Reaction

Clinical Significance

The Philadelphia chromosome (Ph) is a translocation between chromosome 9 and 22 t(9;22) (q34;Q11) that is found in more than 90-95% of chronic myeloid leukemia (CML), and in 20-25% of adult and 2-10% of childhood acute lymphoblastic leukemia (ALL).  In CML, most translocations fall in the major breakpoint cluster region of the CBR gene, and result in either of two BCR-ABL1 mRNA molecules having an e13a2 junction (fusion of BCR exon 14 with ABL1 exon 2)  that encodes the p210 BCR-ABL1 fusion protein.  In all, about two thirds of the BCR breakpoints fall in the minor breakpoint cluster region of the BCR gene, and the hybrid BCR-ABL1 transcript contains an e1a2 junction (fusion of BCR exon 1 with AB11 exon2) which is translated as a p190 BCR-ABL1 fusion protein.  Quantitative measurement of the changes of BCR-AB1 expression levels over time is important to monitor disease progression and response to targeted therapies.  This test is a reverse-transcription pcr-based quantitative assay which detectes these two major BCR-AB11 mRNA transcripts produced by the t(9;22) chromosomal translocation (p210 and p190).  BCR-ABL1 transcript levels are expressed as a percent ratio of BCR-ABL1 to the normalizing ABL1 transcript levels.  For the p210 transcript associated with CML, quantitation is further adjusted to the international scare (IS) to allow comparison with other IS-complian BCR-ABL1 assays.  Optimal therapy in CML is associated wiht transcript levels below the major molecular response (MMR) milestone indicated by a CBR-ABL1/ABL1% (is) below 0.1.


Production Schedule

Sites Performed
  • Quest - Chantilly
Days Performed
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Departments
  • Sendouts - Miscellaneous
Turn Around Time

4 days


Coding & Compliance

CPT Coding

81207 or 81206 or 81206,81207 (see included tests section)