BCR/ABL, p190, mRNA Detection, Reverse Transcription-PCR (RT-PCR), Quantitative, Monitoring Assay
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Monitoring response to therapy in patients with known e1/a2 bcr/abl (p190) fusion forms
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Quantitative Reverse Transcription-Polymerase Chain Reaction (RT-PCR)
(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
BCR/ABL, p190, Quant, Monitor
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
The following information is required:
1. Pertinent clinical history including if the patient has a diagnosis of chronic myelogenous leukemia (CML) or other bcr/abl-positive neoplasm
2. Date of collection
3. Specimen source (blood or bone marrow)
1. Hematopathology Patient Information Sheet (Supply T676) in Special Instructions
2. If not ordering electronically, please submit a Hematopathology/Molecular Oncology Request Form (Supply T241) with the specimen.
Submit only 1 of the following specimens:
Specimen Type: Whole blood
Preferred: Lavender top (EDTA)
Specimen Volume: 4 mL
1. Invert several times to mix blood.
2. Send specimen in original tube.
3. Label specimen as blood.
Specimen Type: Bone marrow
Preferred: Lavender top (EDTA)
Specimen Volume: 3 mL
1. Invert several times to mix bone marrow.
2. Send specimen in original tube.
3. Label specimen as bone marrow.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Mild OK; Gross reject
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Varies||Ambient (preferred)||72 hours|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
mRNA transcribed from BCR/ABL (fusion of the breakpoint cluster region gene [BCR]at chromosome 22q11 to the Abelson gene [ABL] at chromosome 9q23) is detected in all chronic myelogenous leukemia (CML) patients and a subset of both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) patients. Although breakpoints in the BCR and ABL genes may occur in a variety of locations, splicing of the primary RNA transcripts result in only 8 fusion site variants (e1/a2, e6/a2, e13/a2, e14/a2, e19/a2, and e1/a3, e13/a3, e14/a3), which incorporate the entire sequence of the exons on both sides of the fusion site. The e1/a2 and e1/a3 fusion forms produce a 190-kDa protein designated p190. This bcr/abl protein form is found in approximately 75% of childhood ALL patients and approximately 50% of adult ALL patients, with the majority arising from e1/a2 mRNA. The p190 is also the predominant fusion form in a small subset of CML patients, although the vast majority of CML cases contain the p210 protein, typically from e13/a2 or e14/a2 mRNA fusions. Other fusion forms are very rare.
Quantitative reverse-transcription PCR (qRT-PCR) is the most sensitive method for monitoring bcr/abl levels during treatment. This test detects mRNA coding for the most common p190 fusion form (e1/a2).
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
The presence or absence of the BCR/ABL mRNA (bcr/abl) fusion form producing the p190 fusion protein is reported. If positive, the level is reported as the ratio of bcr/abl (p190) to abl with conversion to a percentage (ie, bcr/abl (p190) as a percentage of total abl).
An interpretive report will be provided.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test detects only the e1/a2 bcr/abl (p190) fusion form. Other fusion forms are not detected by this assay, including those containing the BCR e13 and e14 exons, which code for the p210 protein commonly found in chronic myeloid leukemia (CML).
This test should not be used to monitor patients carrying bcr/abl fusion forms coding for the p210 protein, which includes most CML patients; BCRAB/89007 BCR/ABL, p210, mRNA Detection, Reverse Transcription-PCR (RT-PCR), Quantitative, Monitoring Chronic Myelogenous Leukemia (CML) should be ordered for this purpose.
This test should not be used to screen for bcr/abl fusions at the time of diagnosis; BADX/89006 BCR/ABL, mRNA, Detection, Reverse Transcription-PCR (RT-PCR), Qualitative, Diagnostic Assay should be ordered for this purpose.
The precision of this assay at low bcr/abl levels is relatively poor, such that inter-run variation can be as high as 0.5 log. Only level changes >0.5 log should be considered clinically significant. For example, if a result is given as 0.1% bcr/abl(p190):abl, then any result between 0.05% and 0.5% should be considered essentially equivalent. If the results are being used to make major therapeutic decisions, significant changes during monitoring should be verified with a subsequent specimen.
Results of this assay cannot be directly compared with results generated from other PCR assays, including identical assays performed in other laboratories. Monitoring should be performed using the same method and laboratory for each subsequent specimen.
The results of this assay cannot be directly compared with bcr/abl results obtained using FISH technology. FISH measures DNA alleles and this PCR-based assay measures mRNA transcripts. Because a single DNA allele can produce many mRNA transcripts, the values are not directly comparable.
Blood is the specimen of choice for monitoring. While most patients show similar bcr/abl levels in blood and bone marrow drawn at the same time, some patients have a consistent difference in the levels in blood and bone marrow such that altering specimen types during monitoring can lead to confusion.
Assay precision does not appear to be significantly affected by specimen transport or moderate delays in processing. However, in specimen with very low levels of bcr/abl, these conditions may cause sufficient RNA degradation to produce false-negative results. Thus, specimen should be shipped as quickly as possible and specimens >3 days old at the time of receipt will be considered unacceptable.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Hughes TP, Kaeda J, Branford S, et al: Frequency of major molecular responses to imatinib or interferon alfa plus cytarabine in newly diagnosed chronic myeloid leukemia. N Engl J Med 2003;349:1423-1432
2. Radich JP, Gooley T, Bryant E, et al: The significance of BCR/ABL molecular detection in chronic myeloid leukemia patients "late," 18 months or more after transplantation. Blood 2001;98:1701-1707
3. Olavarria E, Kanfer E, Szydlo R, et al: Early detection of BCR-ABL transcripts by quantitative reverse transcriptase-polymerase chain reaction predicts outcome after allogeneic stem cell transplant for chronic myeloid leukemia. Blood 2001;97:1560-1565
Method Description Describes how the test is performed and provides a method-specific reference
Total RNA is extracted from the sample using the QIAmp kit (Qiagen). cDNA is made using SuperScript III Kit (Invitrogen). A quantitative, real-time-PCR reaction is performed using the LightCycler 2.0 instrument (Roche) with one set of primers designed to detect the bcr/abl e1/e2 fusion and a second set of primers designed to detect a fragment of abl. Taqman-type probe technology is used in both reactions. The data is analyzed using the supplied software for relative quantification with calibrator normalization and efficiency correction. (Roche Applied Science LightCycler 2.0 Instrument Operation Manual, Version 4/1.2. 2003). The abl is amplified to control for RNA degradation in the sample and the calibrator is used to control for inter-run variations. A normalized ratio of bcr/abl(p190) mRNA:abl mRNA is obtained and converted to the reported value of percent bcr/abl(p190):abl.(Unpublished Mayo method)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
RNA: Up to 3 months
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
81207-BCR/ABL1 (t[9;22]) (eg, chronic myelogenous leukemia) translocation analysis; minor breakpoint, qualitative or quantitative
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|MP002||Specimen Type||In Process|