ObjectiveTo investigate a more convenient and safe sampling method for viral nucleic acid detection of coronavirus disease 2019.MethodsAn oropharyngeal swab and nasopharyngeal swab were simultaneously taken from 100 patients with coronavirus disease 2019 in a hospital in Wuhan. Then the efficacies of two sampling methods were compared on the positive rates of viral nucleic acid detection.ResultsThe positive rate for SARS-CoV-2 was 54% in oropharyngeal swabs, while 89% positive in nasopharyngeal swabs. There was a significant difference in the detection rate between oropharyngeal swab and nasopharyngeal swab (χ2=3.850 4, P=0.049 7).ConclusionsThe positive rate for nucleic acid testing from nasopharyngeal swabs are significantly better than that from oropharyngeal swabs. Therefore, sampling by nasopharyngeal swabs, rather than oropharyngeal swabs, should be chosen as the preferred virological screening method for patients with coronavirus disease 2019.
ObjectiveTo evaluate the clinical significance of human immunodeficiency virus (HIV) testing algorithm combining antigen/antibody assay screening with Western Blot (WB) or HIV nucleic acid.MethodsData of HIV antigen and antibody screening samples in West China Hospital of Sichuan University in 2018 were retrospectively analyzed. The 4th generation antigen and antibody reagents were used for initial screening, and the 3rd generation antibody reagents were used for reexamination. WB or HIV nucleic acid detection was performed as supplementary test.ResultsA total of 217 803 samples were initially screened, 718 samples were positive in initial screening (0.33%) and 513 samples were confirmed positive (0.24%). The 718 initial positive samples were confirmed by WB, among them, 513 (71.45%) were positive, 163 (22.70%) were negative, and 42 (5.85%) were indeterminate. Fifteen samples which were negative or indeterminate were detected by HIV RNA, as a result, 6 were positive. Two of four patients turned into positive during follow-up. Among the 536 samples which were positive in both the 4th and 3rd generation assay, there were 513 (95.71%) positive, 6 (1.12%) negative, and 17 (3.17%) indeterminate confirmed by WB; among the 182 samples which were positive in the 4th generation assay but negative in the 3rd generation assay, there were none (0.00%) positive, 157 (86.26%) negative, and 25 (13.74%) indeterminate confirmed by WB. The positive rate of confirmation test of samples positive in the 4th and 3rd generation assay (95.71%, 513/536) was significantly higher than that of samples positive in the 4th generation assay but negative in the 3rd generation assay (0%, 0/182), and the difference was statistically significant (χ2=610.091, P<0.001). WB band types for positive samples were dominated by the whole bands and sub-bands, accounting for 82.26%. The cut off index in ≥5 bands group was higher than that in < 4 bands group (P<0.001).ConclusionsSamples with both the 4th and 3rd generation assay positive have a high positive rate of confirmation test, and a supplementary test is needed to be done as soon as possible to confirm the diagnosis. Samples with only the 4th generation assay positive have a low positive rate of confirmation test. But for patients with a high-risk history, HIV nucleic acid should be done as soon as possible for early diagnosis.
ObjectiveTo use failure mode and effect analysis (FMEA) to check and improve the risk of severe acute respiratory syndrome coronavirus 2 nucleic acid detection, and explore the application effect of FMEA in the emergency inspection items.MethodsFMEA was used to sort out the whole process of severe acute respiratory syndrome coronavirus 2 nucleic acid detection from January 30 to February 21, 2020. By establishing the theme, setting up a team, analyzing the failure mode and potential influencing factors. Then calculate the risk priority number (RPN), formulate preventive measures and implement continuous improvement according to the analysis results.ResultsA total of 2 138 cases were included. After improvement, the number of potential failure modes has been reduced by 2 (17 vs.19); the value of total RPN decreased (3 527.49 vs. 1 858.28). There was significant difference in average RPN before and after improvement [(185.66±74.34) vs. (97.80±37.97); t=6.128, P<0.001].ConclusionsIn the early stage of emergency inspection items, using FMEA can systematically check the risk factors in the process, develop improvement measures. It also can effectively reduce the risk of severe acute respiratory syndrome coronavirus 2 nucleic acid detection in hospital.