tetano
Editor, Senior Moderator
Med Microbiol Immunol
. 2023 Aug 10.
doi: 10.1007/s00430-023-00775-8. Online ahead of print. Ten rapid antigen tests for SARS-CoV-2 widely differ in their ability to detect Omicron-BA.4 and -BA.5
Franziska Krenn[SUP] 1 [/SUP], Christopher Dächert[SUP] 1 2 [/SUP], Irina Badell[SUP] 1 [/SUP], Gaia Lupoli[SUP] 1 [/SUP], Gamze Naz Öztan[SUP] 1 [/SUP], Tianle Feng[SUP] 1 [/SUP], Nikolas Schneider[SUP] 1 [/SUP], Melanie Huber[SUP] 1 [/SUP], Hanna Both[SUP] 1 [/SUP], Patricia M Späth[SUP] 1 [/SUP], Maximilian Muenchhoff[SUP] 1 2 3 [/SUP], Alexander Graf[SUP] 4 [/SUP], Stefan Krebs[SUP] 4 [/SUP], Helmut Blum[SUP] 4 [/SUP], Jürgen Durner[SUP] 5 [/SUP], Ludwig Czibere[SUP] 5 [/SUP], Lars Kaderali[SUP] 6 [/SUP], Oliver T Keppler[SUP] 7 8 9 [/SUP], Hanna-Mari Baldauf[SUP] 10 [/SUP], Andreas Osterman[SUP] 11 [/SUP]
Affiliations
Since late 2021, the variant landscape of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been dominated by the variant of concern (VoC) Omicron and its sublineages. We and others have shown that the detection of Omicron-BA.1 and -BA.2-positive respiratory specimens by rapid antigen tests (RATs) is impaired compared to Delta VoC-containing samples. Here, in a single-center retrospective laboratory study, we evaluated the performance of ten most commonly used RATs for the detection of Omicron-BA.4 and -BA.5 infections. We used 171 respiratory swab specimens from SARS-CoV-2 RNA-positive patients, of which 71 were classified as BA.4 and 100 as BA.5. All swabs were collected between July and September 2022. 50 SARS-CoV-2 PCR-negative samples from healthy individuals, collected in October 2022, showed high specificity in 9 out of 10 RATs. When assessing analytical sensitivity using clinical specimens, the 50% limit of detection (LoD50) ranged from 7.6 × 10[SUP]4[/SUP] to 3.3 × 10[SUP]6[/SUP] RNA copies subjected to the RATs for BA.4 compared to 6.8 × 10[SUP]4[/SUP] to 3.0 × 10[SUP]6[/SUP] for BA.5. Overall, intra-assay differences for the detection of these two Omicron subvariants were not significant for both respiratory swabs and tissue culture-expanded virus isolates. In contrast, marked heterogeneity was observed among the ten RATs: to be positive in these point-of-care tests, up to 443-fold (BA.4) and up to 56-fold (BA.5) higher viral loads were required for the worst performing RAT compared to the best performing RAT. True-positive rates for Omicron-BA.4- or -BA.5-containing specimens in the highest viral load category (C[SUB]t[/SUB] values < 25) ranged from 94.3 to 34.3%, dropping to 25.6 to 0% for samples with intermediate C[SUB]t[/SUB] values (25-30). We conclude that the high heterogeneity in the performance of commonly used RATs remains a challenge for the general public to obtain reliable results in the evolving Omicron subvariant-driven pandemic.
Keywords: Diagnostic test; Lateral flow; Nucleocapsid protein; Omicron; SARS-CoV-2 rapid antigen test; Sensitivity; Specificity; VoC.
. 2023 Aug 10.
doi: 10.1007/s00430-023-00775-8. Online ahead of print. Ten rapid antigen tests for SARS-CoV-2 widely differ in their ability to detect Omicron-BA.4 and -BA.5
Franziska Krenn[SUP] 1 [/SUP], Christopher Dächert[SUP] 1 2 [/SUP], Irina Badell[SUP] 1 [/SUP], Gaia Lupoli[SUP] 1 [/SUP], Gamze Naz Öztan[SUP] 1 [/SUP], Tianle Feng[SUP] 1 [/SUP], Nikolas Schneider[SUP] 1 [/SUP], Melanie Huber[SUP] 1 [/SUP], Hanna Both[SUP] 1 [/SUP], Patricia M Späth[SUP] 1 [/SUP], Maximilian Muenchhoff[SUP] 1 2 3 [/SUP], Alexander Graf[SUP] 4 [/SUP], Stefan Krebs[SUP] 4 [/SUP], Helmut Blum[SUP] 4 [/SUP], Jürgen Durner[SUP] 5 [/SUP], Ludwig Czibere[SUP] 5 [/SUP], Lars Kaderali[SUP] 6 [/SUP], Oliver T Keppler[SUP] 7 8 9 [/SUP], Hanna-Mari Baldauf[SUP] 10 [/SUP], Andreas Osterman[SUP] 11 [/SUP]
Affiliations
- PMID: 37561225
- DOI: 10.1007/s00430-023-00775-8
Since late 2021, the variant landscape of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been dominated by the variant of concern (VoC) Omicron and its sublineages. We and others have shown that the detection of Omicron-BA.1 and -BA.2-positive respiratory specimens by rapid antigen tests (RATs) is impaired compared to Delta VoC-containing samples. Here, in a single-center retrospective laboratory study, we evaluated the performance of ten most commonly used RATs for the detection of Omicron-BA.4 and -BA.5 infections. We used 171 respiratory swab specimens from SARS-CoV-2 RNA-positive patients, of which 71 were classified as BA.4 and 100 as BA.5. All swabs were collected between July and September 2022. 50 SARS-CoV-2 PCR-negative samples from healthy individuals, collected in October 2022, showed high specificity in 9 out of 10 RATs. When assessing analytical sensitivity using clinical specimens, the 50% limit of detection (LoD50) ranged from 7.6 × 10[SUP]4[/SUP] to 3.3 × 10[SUP]6[/SUP] RNA copies subjected to the RATs for BA.4 compared to 6.8 × 10[SUP]4[/SUP] to 3.0 × 10[SUP]6[/SUP] for BA.5. Overall, intra-assay differences for the detection of these two Omicron subvariants were not significant for both respiratory swabs and tissue culture-expanded virus isolates. In contrast, marked heterogeneity was observed among the ten RATs: to be positive in these point-of-care tests, up to 443-fold (BA.4) and up to 56-fold (BA.5) higher viral loads were required for the worst performing RAT compared to the best performing RAT. True-positive rates for Omicron-BA.4- or -BA.5-containing specimens in the highest viral load category (C[SUB]t[/SUB] values < 25) ranged from 94.3 to 34.3%, dropping to 25.6 to 0% for samples with intermediate C[SUB]t[/SUB] values (25-30). We conclude that the high heterogeneity in the performance of commonly used RATs remains a challenge for the general public to obtain reliable results in the evolving Omicron subvariant-driven pandemic.
Keywords: Diagnostic test; Lateral flow; Nucleocapsid protein; Omicron; SARS-CoV-2 rapid antigen test; Sensitivity; Specificity; VoC.