BCR/ABL Molecular Diagnostic Testing

 

The BCR/ABL fusion gene is found in several types of cancer and is typically formed by an exchange of genetic material between the ABL gene on chromosome 9 and the BCR gene on chromosome 22, to form the BCR/ABL fusion gene. This altered chromosome 22 with the BCR/ABL fusion gene is called the Philadelphia chromosome. At a molecular level, the location of the breakage in the BCR gene results in distinct versions of the BCR/ABL fusion product, which in turn, can result in distinct disease phenotypes.

Chronic myelogenous leukemia (CML) is a form of leukemia characterized by increased and unregulated growth of myeloid cells in the bone marrow, with accumulation of these cells in the blood. More than 95% of individuals with CML are positive for BCR/ABL fusion, and express a version called Major BCR/ABL. The BCR/ABL fusion gene is also present in 25 to 30% of cases of adult B-lineage acute lymphoblastic leukemia (ALL), approximately 2% of childhood B-lineage ALL, and in approximately 5% of cases of acute myelogenous leukemia (AML). Roughly one third of BCR/ABL-positive ALL patients express Major BCR/ABL, and two thirds express another form of the fusion gene called Minor BCR/ABL. There are two fusion products commonly associated with the Major BCR/ABL version and one fusion product commonly associated with the Minor BCR/ABL version. The BCR/ABL1 Molecular Diagnostic Testing offered by Genetics Center is able to detect and distinguish between these three BCR/ABL1 fusion products with a detection rate of one BCR/ABL1 positive cell in 1,000 normal cell background.

The BCR/ABL fusion gene is detectable via molecular methods, even with the absence of a cytogenetically visible Philadelphia chromosome. The version of BCR/ABL fusion product expressed in the patient can be determined by molecular diagnostics, thus confirming a diagnosis and allowing specific knowledge of the disease and future treatment. Quantification of BCR/ABL1 fusion gene transcripts can be performed upon request. For further information about BCR/ABL1 quantitative testing, [click here].

REASONS FOR REFERRAL:

  • Confirmation of a clinically suspected diagnosis of CML.
  • Aid in determining the prognosis for patients with ALL.

 

SPECIAL NOTES:

For initial diagnosis or in patients with no previous BCR/ABL1 testing performed, BCR/ABL1-Diagnostic test is recommended to be ordered with reflex to the BCR/ABL1 Quantitative test [click here].

GENETICS CENTER TESTING METHODS:

  • RNA isolated from whole blood or bone marrow is reverse transcribed and subjected to multiplex PCR. The reaction is then analyzed by gel electrophoresis to identify if the BCR/ABL fusion gene is present, and if so, which version of the BCR/ABL fusion product is present.

 

TURN AROUND TIME:

  • ~5 days

 

SPECIMEN REQUIREMENTS AND SHIPPING/HANDLING:

    Type: Blood 

  • Container: EDTA (lavender top) collection tubes
  • Optimal volume of 4 ml, minimum of 2 ml
  • Unacceptable specimens:
    • Specimens with clotted blood
    • Unlabeled/improperly labeled specimens
    • Frozen or previously frozen specimens.
    • Unacceptable specimens will be discarded
  • Unsuitable Specimens:
    • The following specimen types are unsuitable for RNA isolation. Isolation and analysis will be attempted, but results are not guaranteed.
    • Specimens with clots
    • Specimens that arrive more than 24 hours after harvest.
    • Specimens with volumes less than 2 mL.
  •  

    Type: Bone Marrow:

  • Container: Sodium Heparin or EDTA Purple Top tube.
  • Optimal volume of 5 ml, minimum of 3 ml
  • Unacceptable specimens:
    • Unlabeled/improperly labeled specimens
    • Frozen or previously frozen specimens.
    • Unacceptable specimens will be discarded
  • Unsuitable Specimens:
    • The following specimen types are unsuitable for RNA isolation. Isolation and analysis will be attempted, but results are not guaranteed.
    • Specimens with clots
    • Specimens that arrive more than 24 hours after harvest.
    • Specimens with volumes less than 3 mL.

 

Send to:

Genetics Center
211 S. Main Street
Suite AA
Orange, CA 92868
Tel: (714)288-3500

 

REQUIRED FORMS:

 

TEST LIMITATIONS:

  • This test was designed to detect certain types of BCR/ABL, specifically b3a2, b2a2, and e1a2. Other types of BCR/ABL will not be detected by this assay.
  • This test has a lower limit of detection of 1 BCR/ABL positive cell in 1000 normal cells.
  • This test is not designed to quantify the percentage of mutant cells in the population or the absolute expression level of BCR/ABL. If this is desired, please also order the BCR/ABL Quantitative test also offered by Genetics Center [click here].

 

CPT CODES:

  • BCR/ABL Diagnostic:
    • 2013 CPT: 81402
    • Stacked CPT’s: 83891 x1, 83894 x1, 83902 x1, 83900 x1, 83901×10, 88291 x1
  • For BCR/ABL Quantitative CPT Codes [click here].