Exploring External Quality Control Methods for PCR–Polyacrylamide Gel Electrophoresis–Based Lymphocyte Receptor Gene Rearrangement Assays in Korea

Background: The lymphocyte receptor gene rearrangement test is used for clonal analysis to differentiate between malignant lymphoma and benign lymphoproliferative disorders and to confirm minimal residual disease.However, as no external quality control program for polyacrylamide gel electrophoresis-or GeneScan-based lymphocyte receptor gene rearrangement tests is available in Korea, most laboratories conduct external quality control using other methods.Methods: We identified laboratories directly conducting lymphocyte receptor gene rearrangement tests through a survey and distributed positive and negative quality control nucleic acids in two phases in 2022.Additionally, we evaluated the concentration, purity, and integrity of the nucleic acids to ensure the distribution of high-quality quality control materials.Results: All instruments used by each institution had the recommended specifications validated for the assay reagents.The potential causes of false-positive results were the influence of stutter peaks and instrument artifacts.Meanwhile, the potential causes of false-negative results, based on the position of the c set and comparison of results from tubes A, B, and C, included the breakdown of specific reagents, equipment malfunction, and interpretation errors.Conclusions: We confirmed that the qualitative and quantitative results varied despite performing tests using the same DNA and reagents.However, it is important to consider recording both qualitative and quantitative results when implementing an external quality control program.