Comparison of the Effectiveness in the Application of Competitive and Noncompetitive Internal Control for the Laboratory Developed Polymerase Chain Reaction / 대한수혈학회지

BACKGROUND: A nucleic acid amplification test was adopted to detect transfusion-transmitted infectious agents. In the case of HTLV, however, there was no internal control (IC) because the laboratory developed polymerase chain reaction (laboratory-developed PCR) was used. In this study, noncompetitive IC was constructed for the laboratory-developed PCR of HTLV and the effectiveness was compared with the competitive test that was constructed in a previous study. METHODS: As a competitive IC, plasmid DNA, including the primer recognition sequence for the amplification of the HTLV pX region, was constructed. As a noncompetitive IC, an additional primer was constructed for the amplification of the housekeeping gene, the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene. The performance of the competitive and noncompetitive IC was verified and compared using 10 HTLV positive samples and 10 negative samples. In addition, the detection limits in the assay adopting competitive IC and noncompetitive IC were compared. RESULTS: In the case of competitive IC applications, all 10 positive samples were positive and all 10 negative samples were negative. In the case of noncompetitive IC applications, however, one positive sample was not detected. The detection limit of the assay using competitive IC was 100 pg and that of the assay using noncompetitive IC was 1 ng. CONCLUSION: Although the manufacturing processes is not required using noncompetitive IC, the adoption of competitive IC is more effective to ensure the assay results because the ability of detection of the assay adopting competitive IC was better than that using noncompetitive IC.

Construction and Application of Internal Control for Laboratory-Developed HTLV PCR / 대한수혈학회지

BACKGROUND: For donor samples showing reactive results in a human T-cell lymphotropic virus (HTLV) antibody test along with indeterminate results in Western blot assay, HTLV nucleic acid amplification test using laboratory-developed polymerase chain reaction (PCR) was performed. It is necessary to construct an adequate internal control (IC) to evaluate the accuracy of the results since we did not use an IC in the laboratory-developed PCR. METHODS: As a competitive IC, plasmid DNA containing the primer recognition sequence for amplification of the HTLV pX region was constructed. We determined the adequate concentration of the IC, which was added to the samples to evaluate the accuracy of the test results. RESULTS: When the plasmid DNA was added to the HTLV-positive samples, the amplified product of IC (400 bp) was detected with the HTLV gene (230 bp). The adequate concentration of plasmid DNA added as an IC was 1 pg. CONCLUSION: The construction of plasmid DNA as a competitive IC is an efficient method to evaluate accuracy of the test results. However, the production process for the competitive IC must be further developed. Therefore, it is necessary to compare with the performance of a non-competitive IC.