Articles
LIU Ting, OUYANG Zheng-de, WU Wen-jin, LIN Xiao-de, FENG Zhi-gang
Objective Extraction of nucleic acid of SARS-CoV-2 with releasing agent by one-step method was optimized to improve the detection rate of the internal control (IC) in RT-PCR, reduce the re-examination rate caused by the non-detection of IC, and improve the time efficiency of report. Methods The nucleic acid test samples of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from the PCR laboratory of Bao'an Hospital of Traditional Chinese Medicine, were applied to extract nucleic acid with releasing agent one-step method that optimized by the laboratory, and compared with the original method in the kit specification: To observe the changes of IC amplification curve and cycle threshold(Ct); to compare the change of the review rate before and after. Results The amplification curves of IC were scattered between Ct24-44 before the optimization, and there were no amplification curves in several samples when unoptimized. After the optimization, the amplification curves were concentrated in the range of Ct 22-34,and all showed typical "S" shape; the Ct of samples were significantly lower than that before the optimized (t=5.937 0, P<0.01), meanwhile, there were no difference between the Ct of N and ORF1a/b gene in the positive control before and after optimization (P>0.05); the Ct of N (F=1.032, P=0.970 1) and ORF1a/b (F=1.262, P=0.784 8) gene in the positive quality evaluation samples were in the same case (P>0.05). The overall sample review rate was also significantly reduced (F=3.899 0, P=0.025 8). Conclusion The optimized one-step method for nucleic acid extraction is simple, convenience, and short test time. Without affecting the Ct of N and ORF1a/b gene in the SARS-CoV-2 positive samples, the results after amplification are obviously better than before, and reduced the rate of review, shorted the reporting time, which ease the burden of the huge detection pressure.