Rapid antigen and antibody microfluidic immunofluorescence assays compared to culture, PCR, and laboratory reference tests: Performance in a longitudinal cohort.

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