Abstract
Introduction: The pandemic of a novel coronavirus disease 2019 (COVID-19) caused by a severe acute respiratory coronavirus 2 (SARS-CoV-2) infection has been problematic worldwide. A new SARS-CoV-2 diagnostic test (SmartAmp) was licensed in Japan in July 2021. This method, which enables us to diagnose COVID-19 as well as a gene mutation on the virus, is promising to reduce medical costs and staff labor.
Patients and methods: To analyze the diagnostic accuracy of the SmartAmp assay for diagnosing COVID-19, we performed this retrospective study at our institute during April and May 2021. We compared the results of the SmartAmp assay and real-time reverse transcription-polymerase chain reaction (rRT-PCR) using a saliva sample from individuals suspected as having COVID-19.
Results: Out of 70 samples tested, the SmartAmp assay had 50 (71%) positive and 20 (29%) negative results. Using rRT-PCR as a reference, the diagnostic accuracy displayed a sensitivity of 84%, a specificity of 95%, a positive predictive value of 97.7%, and a negative predictive value of 70.4%. On the other hand, false-negative cases were found in 7 (10%), and there was no significant difference of Ct-value between true positive and false negative cases (Mean Ct-value 25.2 vs. 27.5 cycles, p = 0.226 by Mann-Whitney U test).
Conclusion: The SmartAmp assay is a valuable method to diagnose COVID-19 rapidly. However, the negative predictive value is not high enough to diagnose the disease, so that negative results should be considered for rRT-PCR testing if patients are suspected of having COVID-19.
Keywords: COVID-19; Coronavirus; Reverse transcription-polymerase chain reaction; SARS-CoV-2; SmartAmp.
【저자키워드】 COVID-19, SARS-CoV-2, coronavirus, Reverse transcription-polymerase chain reaction, SmartAmp., 【초록키워드】 coronavirus disease, Saliva, Coronavirus disease 2019, coronavirus, pandemic, Mutation, diagnostic test, Infection, diagnostic, novel coronavirus disease, virus, Novel coronavirus, Predictive value, Retrospective study, polymerase chain reaction, sensitivity, specificity, rRT-PCR, Diagnostic accuracy, Positive predictive value, Accuracy, Patient, Japan, Ct-value, respiratory, false-negative, diagnose, False negative, Reverse transcription-polymerase chain reaction, severe acute respiratory coronavirus 2, Negative predictive value, Chain Reaction, medical costs, not high, no significant difference, individual, severe acute respiratory coronavirus, diagnosing, positive, Mann-Whitney U test, rRT-PCR testing, Respiratory Coronavirus, new SARS-CoV-2, tested, performed, caused, the disease, reduce, 【제목키워드】 Saliva, Comparative, specimen, diagnosing,