[Quality assurance of the molecular diagnostic tests in hematological malignancies]

Analyses of nucleic acid sequences in hematological malignancies are now essential in managing patients with hematological malignancies. Because of the impact of the test on decision-making in patient care, its accuracy is quite important. Detection of BCR-ABL mRNA by polymerase chain reaction, one of the most popular molecular diagnostic tests for hematological malignancies, has been used for diagnosis of Philadelphia-positive leukemias. Quality of the test must be assured in the process of diagnostic plan, sampling, measurement(nucleic acid isolation, amplification, detection), report and interpretation. Risk of false-positive results due to contamination of in vitro nucleic acid amplification reactions can be decreased through the use of protocols for contamination control. False-negative results may be caused by variability in BCR breakpoint, and loss or degradation of RNA due to inappropriate procedures as well as an insufficient detection sensitivity. Presence of inhibitors of amplification is also to be considered as a cause of false-negative results. Thus, quality control techniques such as internal standards are mandatory to ensure efficient amplification as well as RNA extraction. For the precise evaluation of minimal residual diseases, accurate and sensitive quantitative analyses are required. For quality assurance of assays in the present status of no commercially available kits, it is particularly important to monitor the clinical validation of the results by correlating them with the patient's status to prove clinically relevant. Staffs need to be trained to be familiar with both molecular pathogenesis and technology so that they can provide informative test results with a high quality.