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BCR / ABL p210 Quantitative RT-PCR Assay

Technical Brief

BCR / ABL p210 Quantitative RT-PCR Assay with International Scale Reporting for Minimal Residual Disease in Chronic Myeloid Leukemia


Test Name

BCR / ABL p210 RT-PCR, quantitative (BCRPCR)

CPT Code

81206
G0452

Methodology

Reverse Transcription/Polymerase Chain Reaction (RT/PCR)

Turnaround Time

5 – 7 days

Specimen Requirements

Clients should ship specimens as “Priority Overnight” to ensure specimen stability.

Do not ship on Fridays or the day preceding a holiday.

Specimen Type:
Whole blood

Volume:
10 mL

Minimum Volume:
4 mL

Collection Container:
Lavender BD Hemogard™ K2EDTA Tube

Transport Temperature:
Ambient

Clearly indicate specimen type on the label.

Alternative Specimen

Specimen Type:
Bone marrow

Volume:
5 mL

Minimum Volume:
2 mL

Collection Container:
Lavender BD Hemogard™ K2EDTA Tube

Transport Temperature:
Ambient

Clearly indicate specimen type on the label.

Stability

Ambient:
48 hours

Refrigerated:
7 days

Ambient:
Unacceptable

Reference Range

BCR ABL p210 transcripts not detected

Additional Information

Background Information

A translocation between chromosomes 9 and 22, resulting in the formation of a BCR / ABL fusion transcript, has long been recognized as a hallmark of chronic myeloid leukemia (CML). Although the breakpoints in BCR and ABL are variable, in >95% of cases of CML, the translocation results in production of the p210 isoform of the fusion protein (e13a2 or e14a2 fusion genes).

Modern therapy for CML, including tyrosine kinase inhibitors, has resulted in effective therapeutic options for CML patients. With this advance in treatment has come the need for effective monitoring for the presence of minimal residual disease (MRD) and the ability to recognize disease progression at an early stage. Techniques such as fluorescence in situ
hybridization (FISH) and metaphase cytogenetics provide valuable information at the time of initial diagnosis of CML and metaphase cytogenetics is helpful for identifying the emergence of additional chromosomal abnormalities, however, neither of these techniques are sufficiently sensitive to monitor MRD.[1],[2] For this reason, a BCR ABL p210 quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) assay was developed, validated, and implemented in the Department of Molecular Pathology.

To facilitate comparison of quantitative RT-PCR results between laboratories and platforms, International Scale reference materials were established by the World Health Organization.[3] Results of this assay are now reported on the International Scale.

Clinical Indications

Quantitative detection of BCR/ABL p210 transcripts (e13a2 or e14a2) in patients with CML.

Methodology

Assay sensitivity was established using RNA extracted from K562 cultured cells suspended in normal buffy coat. This assay successfully detects p210 BCR ABL transcripts in RNA extracted from one K562 cell in 100,000 peripheral blood leukocytes from a normal individual.

Interpretation

Results are reported as the percentage ratio of fusion gene transcripts to wild-type ABL transcripts (% BCRABL ABL).

Results are also converted to the International Scale. A BCRABL ABL value of 0.1% on the International Scale represents a major molecular response by consensus criteria.

References

1. Hughes T, Deininger M, Hochhaus A et al. Monitoring CML patients responding to treatment with tyrosine kinase inhibitors: review and recommendations for harmonizing current methodology for detecting BCRABL transcripts and kinase domain mutations and for expressing results. Blood. 2006;108:28-37.

2. Druker BJ, Guilhot F, O’Brien SG et al. Five-year follow-up of patients receiving imatinib for chronic myelogenous leukemia. N Engl J Med. 2006;355:2408-2417.

3. White HE, Matejschuk P, Rigsby P, et al. Establishment of the first World Health Organization International Genetic Reference Panel for quantification of BCRABL mRNA. Blood 2010;116:e111-7.