Lab Test

Test Definition Number : 37
Test Definition Name : BCR-ABL1 t(9;22) translocation detection
Lab Name : OHSU Knight Diagnostics Lab
Lab Test Number of THIS Version : 1173
Lab Test Name : BCR-ABL RNA PCR Quantiation
Status : Active
Expired : No
Updated : 2018-01-27 21:53 EST

General Attributes

Chromosome Band : 9q34.11
22q11.22
HUGO Gene Name : [ABL1] ABL proto-oncogene 1, non-receptor tyrosine kinase
[BCR] breakpoint cluster region
ICD-Oncology Code
(includes WHO classification diagnoses)
: [9875/3] Chronic myelogenous leukemia, BCR/ABL positive

Infectious Disease Attributes

Agent Category :
Non-virus Genus and Species :
Virus Family, Genus, and Species :

Lab-specific Attributes

Method : Polymerase Chain Reaction (PCR) - Real Time
Polymerase Chain Reaction (PCR) - Reverse Transcriptase
Specimen Source
(for clinical patient care these sources must be validated)
:
ICD-10 Code :
Use :
Genetics Category : Acquired (somatic)
SNOMED CT :
LOINC :
Comments : Background: Chronic myeloid leukemia (CML) is a clonal hematologic stem cell malignancy associated, in greater than 90% of cases, with the Philadelphia chromosome (Ph), a reciprocal translocation between the long arms of chromosomes 9 and 22 [t(9;22)(q34;q11)]. The molecular consequences of the Philadelphia translocation are the physical juxtapositioning of sequences from the chromosome 22 BCR gene (breakpoint cluster region) adjacent to sequences from the chromosome 9 c-ABL gene encoding a non-receptor tyrosine kinase. The resulting BCR-ABL fusion gene is transcribed and translated into a 210 kD (p210) or 190 kD (p190) BCR-ABL fusion product with dysregulated (significantly enhanced) tyrosine kinase activity. The aberrant growth and differentiation of leukemic cells in CML is caused by the constitutive expression of the BCR-ABL kinase, a chimeric fusion protein resulting from a leukemia-specific chromosomal translocation described above. Targeted inhibition of BCR-ABL with tyrosine kinase inhibitors (imatinib, dasatinib, nilotinib) is the standard treatment for CML (and Ph+ ALL). The efficacy of TKI therapy is routinely monitored with serial BCR-ABL RNA PCR’s, which define the “molecular response”. A consensus treatment goal is the achievement of “major molecular response”, a 3-log drop in BCR-ABL RNA, defined as 0.1% on the BCR-ABL RNA PCR international scale (IS) of measurement. Clinical Utility: The quantitative BCR-ABL RNA assay is intended to monitor the level of minimal residual disease in TKI-treated Philadelphia chromosome positive leukemias (CML or ALL). High or rising BCR-ABL RNA levels have been shown to increase the risk of leukemic relapse and drug-resistance mutations during TKI therapy. The failure to achieve a “major molecular response”, a 3-log drop in BCR-ABL RNA, defined as 0.1% on the BCR-ABL RNA PCR international scale (IS), is the consensus definition of a “sub-optimal” treatment that requires an alternative treatment approach. The OHSU BCR-ABL RNA PCR assay has been calibrated to the International Scale, and is one of only a few US assays reporting results on the IS. Methodology: By measuring BCR-ABL RNA levels using a sensitive real-time fluorescent PCR method, we are able to detect the presence of leukemic cells at a very low level. The sensitivity limit of the assay is approximately 1 tumor cell in 100,000 normal cells. A relative ratio (in percent) of BCR-ABL RNA to reference gene RNA is reported, as well as a value on the BCR-ABL international scale (which is the only way to assess major molecular response).
Specimen Transport Requirements : Blood or Bone Marrow: 10-20 mL purple (EDTA) or yellow (ADC) tube (unspun) Deliver to lab at shipping address above within 24 hours of collection, if sample cannot arrive within 24 hours, refrigerate until sample can be transported, then transport on ice packs; do not freeze. If sample is to be shipped overnight, pour blood/bone marrow into RPMI media at a 1:1 ratio (1 mL of RPMI to 1 mL of blood/bone marrow) and mix thoroughly. If our lab is used to monitor the patient’s BCR-ABL1 RNA levels (by RQ-PCR), the same sample that was used for quantitative PCR can also be used for sequencing. We routinely store these samples (stabilized) for several weeks after RQ-PCR reporting. Please call Client Services at (855) 535-1522 to order sequencing. Keep specimen cold during transit, but do not ship on dry ice. Contact Client Services for shipping kit and instructions at (855) 535-1522. Please use the cold pack provided in the KDL shipping kit. Ship the specimen overnight express, using the FedEx priority overnight label provided. The specimen must arrive at the lab no more than 24 hours after collection.
Samples Available for Proficiency Test Sample Exchange : Yes

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