新型冠状病毒快速抗原检测与核酸检测结果一致与不一致因素探讨

A Study of the Consistent and Inconsistent Factors Between Rapid Antigen Testing and Nucleic Acid Detection of COVID-19

目的研究发热患者新型冠状病毒快速抗原筛查(以下简称“抗原检测”)与新型冠状病毒核酸检测(以下简称“核酸检测”)的一致性,探讨其不一致的因素。方法回顾2022年11月28日至2022年12月11日本院发热门诊的发热患者158例(新冠核酸阴性患者82例,新冠核酸阳性患者76例),对每位患者采集鼻咽拭子,用胶体金免疫层析法进行抗原检测;同时在1支胍盐灭活的病毒采样管内采集鼻咽和口咽两支拭子,采用实时荧光定量反转录PCR方法检测新型冠状病毒核酸,评价抗原检测结果与核酸循环阈(Ct)值的相关性;按照Ct值对样本分组(Ct<25、25≤Ct≤30、30<Ct<35),进行统计分析;再对Ct<25且抗原检测为阴性的10例样本进行后序追踪分析。结果发热0.5~5d,体温在37.5~39.8℃的158例患者,82例抗原检测与核酸检测均阴性,抗原检测与核酸检测的一致性为100%;76例核酸检测阳性患者,抗原检测与核酸检测的一致性为75.7%(54/76),其中核酸检测Ct值<25,抗原检测的阳性检出率为82.1%(46/56),Ct值25≤Ct≤30,抗原检测的阳性检出率为66.6%(8/12),Ct值30<Ct<35,抗原检测的阳性检出率为0%(0/8)。结论新型冠状病毒感染以核酸检测结果为金标准,胶体金法抗原检测阳性,可作为发热患者新型冠状病毒感染快速辅助诊断方法。抗原检测阳性检出率与病毒核酸载量成正相关。抗原检测阴性,不能完全排除新型冠状病毒感染,应采取核酸检测以明确诊断。

Objective To investigate the consistencies in results between rapid antigen testing for COVID-19(hereinafter referred to as“antigen testing”)and nucleic acid testing for COVID-19(hereinafter referred to as“nucleic acid detection”)in febrile patients,and to explore potential reasons causing inconsistencies.Methods A total of 158 febrile patients(82 with negative nucleic acid results and 76 with positive)admitted at our fever clinic from November,28 to December,11,2022 were retrospectively analyzed.Nasopharyngeal swabs were collected from each patient for antigen testing using colloidal gold immunochromatography;Two swabs were also collected from the nasopharynx and oropharynx in one guanidine salt-inactivated virus sampling tube for COVID-19 nucleic acid detection by real-time fluorescent quantitative RT-PCR.Analyses were conducted to determine the correlation between antigen testing results and nucleic acid circulation thresholds(Ct).All samples were grouped according to levels of Ct values(Ct<25,25≤Ct≤30,30<Ct<35)and then statistically analyzed.10 samples with Ct<25 and negative antigen testing results were subsequently followed up in a posterior sequence.Results Among 158 patients with fever for 0.5 to 5 days and body temperature between 37.5℃and 39.8℃,82 cases were negative for both antigen and nucleic acid detection,and the consistency between antigen testing and nucleic acid detection was 100%.In 76 patients with positive COVID-19,the consistency between antigen testing and nucleic acid detection was 75.7%(54/76),among which the positive rate of antigen testing was 82.1%(46/56)for Ct<25,66.6%(8/12)for 25≤Ct≤30,and 0%(0/8)for 30<Ct<35.Conclusion The results of nucleic acid detection can serve as a gold standard for diagnosing COVID-19 infections,whereas positive antigen testing by colloidal gold method can be used as a rapid adjunctive diagnostic method for COVID-19 infection in febrile patients.The positive rate of antigen testing is positively correlated with the nucleic acid load of the virus.Our results suggest that we cannot exclude COVID-19 infection events entirely from a negative antigen test,so a nucleic acid test should be performed in order to further confirm the diagnosis.