ARUP's Laboratory Test Directory
| 0051066: BCR-ABL, t(9;22) Translocation Quantitative Assay by RT-PCR |
| Test Mnemonic: BCRABL QNT | |
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Methodology: Reverse Transcription Polymerase Chain Reaction/Fluorescence Monitoring
Performed: RNA isolation: Sun-Sat; Assay: Varies Reported: 2-7 days |
| Specimen Required: | |
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Collect: One 5 mL lavender (EDTA), pink (K2 EDTA), yellow (ACD Solution A), green (sodium or lithium heparin), lt. blue (sodium citrate), or 3 mL bone marrow.
Transport: 5 mL whole blood or 3 mL bone marrow at 2-8°C. (Min: 1 mL) Remarks: Specimens must be received within 48 hours of collection due to lability of RNA. Stability: Ambient: 1 hour; Refrigerated: 48 hours; Frozen: Unacceptable |
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| Reference Interval: |
| By report |
| Interpretive Data: | |
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This assay is designed to monitor BCR-ABL transcript levels and ideally should be performed prior to the initiation of treatment (see Blood. 2006;108:28-37). Due to assay variation and other factors, the results of this test are not usually directly comparable to results obtained in other laboratories, and only changes in transcript ratios greater than 5-10 fold should be considered potentially significant. A 5-10 fold increase in transcript ratio levels could indicate the emergence of a clone showing kinase inhibitor drug resistance, but should be confirmed prior to making treatment changes. Point mutations in the ABL kinase domain are the most common cause of drug resistance and can be identified using ARUP test # 0040138 BCR-ABL Kinase Domain Mutation assay. Patient RNA is isolated, reverse transcribed (RT) into cDNA, and subjected to PCR amplification using oligonucleotide primers specific for the BCR gene on chromosome 22 and the ABL gene on chromosome 9. These primer sets are designed to detect two gene fusion products: p210 and p190. An additional RT-PCR amplification directed at a human G6PDH gene segment is performed as a control for sample cDNA quality. Each assay includes a positive control reaction using cDNA from a cell line with a known t(9;22) translocation and a negative control reaction using cDNA from a cell line with no evidence of a t(9;22) translocation. PCR products are monitored by real-time PCR using probe sets specific for the G6PDH and ABL genes. BCR-ABL and G6PDH transcripts are quantified by comparison to a standard curve run with each assay. Results are reported as a ratio of BCR-ABL transcripts to G6PDH transcripts. The limit of detection for this assay is at least 1 in 100,000. Results of this test must always be interpreted in the context of morphologic and other relevant data, and should not be used alone for a diagnosis of malignancy. This test was developed and its performance characteristics determined by ARUP Laboratories. The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. |
| CPT Code(s): | |
| 83891 Isolation; 83902 Reverse transcription; 83913 RNA stabilization; 83898 x2 Amplification; 83896 x4 Nucleic acid probes; 83912 Interpretation and report - Additional CPT code modifiers may be required for procedures performed to test for oncologic or inherited disorders. |