Rapid Antigen and Antibody Microfluidic Immunofluorescence Assays Compared to Culture, PCR, and Laboratory Reference Tests: Performance in a Longitudinal Cohort

J Infect Dis. 2023 Oct 18;228(8):1066-1070. doi: 10.1093/infdis/jiad231.

Abstract

We evaluated the performance of rapid antigen (RAg) and antibody (RAb) microfluidic diagnostics with serial sampling of 71 participants at 6 visits over 2 months following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Rapid tests showed strong agreement with laboratory references (κAg = 81.0%; κAb = 87.8%). RAg showed substantial concordance to both virus growth in culture and PCR positivity 0-5 days since symptom onset (κAg-culture = 60.1% and κAg-PCR = 87.1%). PCR concordance to virus growth in culture was similar (κPCR-culture = 70.0%), although agreement between RAg and culture was better overall (κAg-culture = 45.5% vs κPCR-culture = 10.0%). Rapid antigen and antibody testing by microfluidic immunofluorescence platform are highly accurate for characterization of acute infection.

Keywords: COVID-19; SARS-CoV-2; antigen test; infectivity; longitudinal; rapid diagnostic test; serial testing.

Publication types

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

MeSH terms

  • Antibodies
  • COVID-19 Testing
  • COVID-19* / diagnosis
  • Clinical Laboratory Techniques
  • Humans
  • Microfluidics
  • Polymerase Chain Reaction
  • SARS-CoV-2* / genetics
  • Sensitivity and Specificity

Substances

  • Antibodies