QPCR (Quantitative reverse transcriptase polymerase chain reaction)

is a very sensitive test that detects and measures the BCR-ABL gene. QPCR makes thousands of copies of the DNA in cells from a blood or marrow sample to see how many cells have the BCR-ABL gene. Copies of BCR-ABL found by QPCR are also called BCR ABL transcripts. The number of BCR-ABL copies detected by QPCR is called the transcript level. The transcript level reflects the number of BCR-ABL genes in your body. Changes in BCR-ABL levels are measured in logs—a log reduction means the BCR-ABL level has decreased by a certain amount. QPCR can detect one CML cell among more than 100,000 normal cells. This test is used to confirm (diagnose) CML as well as to monitor the treatment response. The QPCR test should always be done in the same lab, preferably a lab that uses the International Scale. The International Scale is a standardized scale for measuring and reporting QPCR test results. QPCR test results from different labs are converted to the International Scale so that all test results are consistent and can be compared between labs.