Performance Characteristics of a Rapid Severe Acute Respiratory Syndrome Coronavirus 2 Antigen Detection Assay at a Public Plaza Testing Site in San Francisco

J Infect Dis. 2021 Apr 8;223(7):1139-1144. doi: 10.1093/infdis/jiaa802.

Abstract

We evaluated the performance of the Abbott BinaxNOW rapid antigen test for coronavirus disease 2019 (Binax-CoV2) to detect virus among persons, regardless of symptoms, at a public plaza site of ongoing community transmission. Titration with cultured severe acute respiratory syndrome coronavirus 2 yielded a human observable threshold between 1.6 × 104-4.3 × 104 viral RNA copies (cycle threshold [Ct], 30.3-28.8). Among 878 subjects tested, 3% (26 of 878) were positive by reverse-transcription polymerase chain reaction, of whom 15 of 26 had a Ct <30, indicating high viral load; of these, 40% (6 of 15) were asymptomatic. Using this Ct threshold (<30) for Binax-CoV2 evaluation, the sensitivity of Binax-CoV2 was 93.3% (95% confidence interval, 68.1%-99.8%) (14 of 15) and the specificity was 99.9% (99.4%-99.9%) (855 of 856).

Keywords: COVID-19; Point of Care testing; Rapid Antigen Test; SARS-CoV-2.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Antigens, Viral / isolation & purification*
  • Asymptomatic Infections
  • COVID-19 / diagnosis*
  • COVID-19 / transmission
  • COVID-19 / virology
  • COVID-19 Testing / instrumentation*
  • COVID-19 Testing / statistics & numerical data
  • Female
  • Humans
  • Male
  • Middle Aged
  • Point-of-Care Testing / statistics & numerical data*
  • RNA, Viral / isolation & purification
  • Reagent Kits, Diagnostic / statistics & numerical data
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / immunology
  • SARS-CoV-2 / isolation & purification*
  • San Francisco
  • Sensitivity and Specificity
  • Time Factors
  • Viral Load
  • Young Adult

Substances

  • Antigens, Viral
  • RNA, Viral
  • Reagent Kits, Diagnostic