J Infect Chemother . Accuracy of rapid antigen detection test for nasopharyngeal swab specimens and saliva samples in comparison with RT-PCR and viral culture for SARS-CoV-2 detection

[tetano]

J Infect Chemother


. 2021 Apr 17;S1341-321X(21)00117-3.
doi: 10.1016/j.jiac.2021.04.010. Online ahead of print.
Accuracy of rapid antigen detection test for nasopharyngeal swab specimens and saliva samples in comparison with RT-PCR and viral culture for SARS-CoV-2 detection


Yoshifumi Uwamino ¹ , Mika Nagata ² , Wataru Aoki ² , Terumichi Nakagawa ² , Rika Inose ² , Hiromitsu Yokota ² , Yuri Furusawa ³ , Yuko Sakai-Tagawa ³ , Kiyoko Iwatsuki-Horimoto ³ , Yoshihiro Kawaoka ⁴ , Naoki Hasegawa ⁵ , Mitsuru Murata ⁶ , Keio Donner Project Members



Affiliations

• PMID: 33934920
• DOI: 10.1016/j.jiac.2021.04.010

Abstract

Introduction: Rapid antigen detection (RAD) tests are convenient tools for detecting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in clinics, and testing using saliva samples could decrease the risk of infection during sample collection. This study aimed to assess the accuracy of the SARS-CoV-2 RAD for testing of nasopharyngeal swab specimens and saliva samples in comparison with the RT-PCR tests and viral culture for detecting viable virus.
Methods: One hundred seventeen nasopharyngeal swab specimens and 73 saliva samples with positive results on RT-PCR were used. Residual samples were assayed using a commercially available RAD test immediately, and its positivity was determined at various time points during the clinical course. The concordance between 54 nasopharyngeal swab samples and saliva samples that were collected simultaneously was determined. Viral culture was performed on 117 samples and compared with the results of the RAD test.
Results: The positive rate of RAD test using saliva samples was low throughout the clinical course. Poor concordance was observed between nasopharyngeal swab specimens and saliva samples (75.9%, kappa coefficient 0.310). However, a substantially high concordance between the RAD test and viral culture was observed in both nasopharyngeal swab specimens (86.8%, kappa coefficient 0.680) and saliva samples (95.1%, kappa coefficient 0.643).
Conclusions: The sensitivity of the SARS-CoV-2 RAD test was insufficient, particularly for saliva samples. However, a substantially high concordance with viral culture suggests its potential utility as an auxiliary test for estimating SARS-CoV-2 viability.

Keywords: Nasopharyngeal swabs; Rapid antigen detection test; SARS-CoV-2; Saliva; Viral culture.

[JJackson]

Conclusions: The sensitivity of the SARS-CoV-2 RAD test was insufficient, particularly for saliva samples. However, a substantially high concordance with viral culture suggests its potential utility as an auxiliary test for estimating SARS-CoV-2 viability.

This is about right IMO an anitgen is the wrong tool to use in place of PCR for COVID diagnosis in symptomatic patients but is perfect, and better than antibody tests due to the time taken for antibody production to ramp up, in finding infected individuals who are a risk to those around them but do not know they are shedding high concentrations of SARS-CoV-2. The tables in the paper show they work well when there is culturable virus but not reliably a week or more after symptom onset when symptoms are rising but the virus has fallen to much lower levels.

[bertrand789]

So in terms of efficiency, at the societal level, the choice is?

https://zh.wikipedia.org/wiki/%E6%95%88%E7%8E%87