Abstract
Purpose: From April to September 2020, Poland was minimally affected by COVID-19 compared to other EU countries. We aimed to investigate the risks of false reverse transcription polymerase chain reaction (RT-PCR) results during the first wave (compared to later waves), that rises when cycle threshold (Ct) of positive result is close to limit of detection (LOD).
Materials/methods: We analyzed Ct values of SARS-CoV-2 positive RT-PCR results of 7726 patients in Poland from April-September 2020. SARS-CoV-2 positive RT-PCR results of 14,534 patients in the 2nd-3rd wave and 10,861 patients in the 4th-5th pandemic waves were used. Statistical analysis was based on one-way analysis of variance. To verify, 95% confidence intervals with Bonferroni correction were computed. Incidence of SARS-CoV-2 variants in Poland was analyzed using Whole Genome Sequencing from 923 (3.6%) patients.
Results: The mean Ct of RT-PCR positive test results analyzed ranged between 22.89 and 26.71 depending on the month of the results collection. The differences between months were significant (p < 0.001). Differences in Ct were observed between age groups, with younger patients displaying higher Ct values, however, major trends over time were paralleled between age groups.
Conclusions: The mean Ct of the tested RT-PCR positive test results was lower than 35 which is considered an upper borderline for reliable positive results of the assay. Therefore, most COVID-19 cases recorded in Poland from April to September 2020 were detected with minor risks of inaccuracy. Data from a single center exhibited greater consistency for both virus Ct level and SARS-CoV-2 virus variant identification.
Keywords: COVID-19; Diagnostic; Epidemiology; Molecular testing; Nucleic acid amplification test.
【저자키워드】 COVID-19, Epidemiology, diagnostic, molecular testing, Nucleic acid amplification test., 【초록키워드】 pandemic, variant, SARS-CoV-2 variant, risk, SARS-CoV-2 virus, Poland, RT-PCR, virus, amplification, cycle threshold, Patient, limit of detection, age, reverse transcription, First wave, patients, Analysis, analysis of variance, 95% confidence interval, COVID-19 case, positive result, single center, positive test result, Bonferroni correction, inaccuracy, difference, polymerase chain, SARS-CoV-2 positive RT-PCR, greater, tested, analyzed, affected, exhibited, were used, groups, displaying, recorded, ranged, younger patient, 【제목키워드】 SARS-CoV-2, pandemic, SARS-CoV-2 variant, Poland, diagnostics, early stage, RT-PCR test, Analysis,