Diagnostic methods based on SARS-CoV-2 antigens detection are a promising alternative to SARS-CoV-2 RNA amplification. We evaluated the automated chemiluminescence-based Lumipulse® G SARS-CoV-2 Ag assay on saliva samples, using Simplexa™ COVID-19 Direct assay as a reference test. Analytical performance was established on a pool of healthy donors’ saliva samples spiked with the 2019-nCoV/Italy-INMI1 isolate, whereas clinical performance was assessed on fresh saliva specimens collected from hospitalized patients with suspect or confirmed COVID-19 diagnosis. The limit of detection (LOD) was 0.65 Log TCID50/mL, corresponding to 18,197 copies/mL of SARS-CoV-2 RNA. Antigen concentrations and SARS-CoV-2 RNA were highly correlated (r = 0.99; p < 0.0001). Substantial agreement (80.3%) and significant correlation (r = −0.675; p = 0.0006) were observed between Lumipulse® G assay results and Ct values on clinical samples, with 52.4% sensitivity and specificity 94.1%. Sensitivity exceeded 90.0% when calculated on samples with Ct < 25, and specificity was 100% when excluding samples from recovered patients with previous COVID-19 diagnosis. Overall, chemiluminescence-based antigen assay may be reliably applied to saliva samples to identify individuals with high viral loads, more likely to transmit the virus. However, the low positive predictive value in a context of low SARS-CoV-2 prevalence underscores the need for confirmatory testing in SARS-CoV-2 antigen-positive cases.

Amendola, A., Sberna, G., Lalle, E., Colavita, F., Castilletti, C., Menchinelli, G., Posteraro, B., Sanguinetti, M., Ippolito, G., Bordi, L., Capobianchi, M. R., Saliva is a valid alternative to nasopharyngeal swab in chemiluminescence-based assay for detection of sars-cov-2 antigen, <<JOURNAL OF CLINICAL MEDICINE>>, 2021; 10 (7): 1471-N/A. [doi:10.3390/jcm10071471] [http://hdl.handle.net/10807/198186]

Saliva is a valid alternative to nasopharyngeal swab in chemiluminescence-based assay for detection of sars-cov-2 antigen

Menchinelli, Giulia;Posteraro, Brunella;Sanguinetti, Maurizio;
2021

Abstract

Diagnostic methods based on SARS-CoV-2 antigens detection are a promising alternative to SARS-CoV-2 RNA amplification. We evaluated the automated chemiluminescence-based Lumipulse® G SARS-CoV-2 Ag assay on saliva samples, using Simplexa™ COVID-19 Direct assay as a reference test. Analytical performance was established on a pool of healthy donors’ saliva samples spiked with the 2019-nCoV/Italy-INMI1 isolate, whereas clinical performance was assessed on fresh saliva specimens collected from hospitalized patients with suspect or confirmed COVID-19 diagnosis. The limit of detection (LOD) was 0.65 Log TCID50/mL, corresponding to 18,197 copies/mL of SARS-CoV-2 RNA. Antigen concentrations and SARS-CoV-2 RNA were highly correlated (r = 0.99; p < 0.0001). Substantial agreement (80.3%) and significant correlation (r = −0.675; p = 0.0006) were observed between Lumipulse® G assay results and Ct values on clinical samples, with 52.4% sensitivity and specificity 94.1%. Sensitivity exceeded 90.0% when calculated on samples with Ct < 25, and specificity was 100% when excluding samples from recovered patients with previous COVID-19 diagnosis. Overall, chemiluminescence-based antigen assay may be reliably applied to saliva samples to identify individuals with high viral loads, more likely to transmit the virus. However, the low positive predictive value in a context of low SARS-CoV-2 prevalence underscores the need for confirmatory testing in SARS-CoV-2 antigen-positive cases.
2021
Inglese
Amendola, A., Sberna, G., Lalle, E., Colavita, F., Castilletti, C., Menchinelli, G., Posteraro, B., Sanguinetti, M., Ippolito, G., Bordi, L., Capobianchi, M. R., Saliva is a valid alternative to nasopharyngeal swab in chemiluminescence-based assay for detection of sars-cov-2 antigen, <<JOURNAL OF CLINICAL MEDICINE>>, 2021; 10 (7): 1471-N/A. [doi:10.3390/jcm10071471] [http://hdl.handle.net/10807/198186]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10807/198186
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