Diagnosis of COVID is performed by PCR methods, but their capacity is limited by the requirement of high-level facilities and instruments. The loop-mediated isothermal amplification (LAMP) method has been utilized for the detection of isolated virus-specific RNA. Preliminary data suggest the possibility of isothermal amplification directly from respiratory samples without RNA extraction. All patients admitted to our hospital were screened for SARS-CoV-2 by routine. Respiratory samples were tested by variplex system based on LAMP method directly without RNA extraction and by PCR. Primary endpoint was the false-negative rate of variplex test compared with PCR as gold standard. In 109 patients variplex test and PCR assay were performed simultaneously. Median age was 80 years and male/female ratio was 40/60%. The prevalence of PCR-confirmed COVID diagnosis was 43.1%. Variplex test was positive in 13.8%. False-negative rate of variplex test compared with PCR was 83.0%. The potential of LAMP technology using isolated RNA has been demonstrated impressively by others, and excellent sensitivity and specificity of detecting SARS-CoV-2 has been reported. However, without RNA extraction, the variplex test system failed to reliably detect SARS-CoV-2 directly in respiratory samples.
【저자키워드】 SARS-CoV-2, COVID-19 diagnostic testing, Loop-mediated isothermal amplification, infectious disease outbreaks, Specificity and sensitivity, False-negative reactions, 【초록키워드】 hospital, RNA, COVID, Prevalence, RNA extraction, PCR, Sensitivity and specificity, Patient, age, isothermal amplification, respiratory, false-negative rate, Respiratory samples, Endpoint, PCR-confirmed, gold standard, PCR assay, positive, respiratory sample, isolated RNA, tested, performed, detect, reported, screened, demonstrated, COVID diagnosis, 【제목키워드】 RNA extraction, respiratory sample, detect,