UMMS Affiliation

Division of Infectious Diseases and Immunology, Department of Medicine; Department of Pediatrics; UMass Center for Clinical and Translational Science; Department of Emergency Medicine; Division of Biostatistics and Health Services Research, Department of Population and Quantitative Health Sciences; Department of Medicine, Division of Cardiovascular Medicine

Publication Date


Document Type

Article Postprint


Diagnosis | Epidemiology | Immunology of Infectious Disease | Immunoprophylaxis and Therapy | Infectious Disease | Microbiology | Virus Diseases


BACKGROUND: Serial screening is critical for restricting spread of SARS-CoV-2 by facilitating the timely identification of infected individuals to interrupt transmission chains. The variation in sensitivity of different diagnostic tests at different stages of infection has not been well documented.

METHODS: This is a longitudinal study of 43 adults newly infected with SARS-CoV-2. All participants provided daily samples for saliva and nasal swab RTqPCR, Quidel SARS Sofia antigen FIA, and live virus culture.

RESULTS: We show that both RTqPCR and the Quidel SARS Sofia antigen FIA peak in sensitivity during the period in which live virus is detected in nasal swabs, but the sensitivity of RTqPCR tests rises more rapidly prior to this period. We also estimate the sensitivities of RTqPCR and antigen tests as a function of testing frequency.

CONCLUSIONS: RTqPCR tests are more effective than antigen tests at identifying infected individuals prior to or early during the infectious period and thus for minimizing forward transmission (given timely results reporting). All tests showed > 98% sensitivity for identifying infected individuals if used at least every three days. Daily screening using antigen tests can achieve ~90% sensitivity for identifying infected individuals while they are viral culture positive.


Diagnostic testing, RTqPCR testing, SARS-CoV-2, antigen testing, test sensitivity, COVID-19

Rights and Permissions

Copyright © 2021, Oxford University Press. This is a PDF file of an accepted manuscript that has been accepted for publication and posted with a 12-month embargo as allowed by the publisher’s self-archiving policy at

DOI of Published Version



Smith RL, Gibson LL, Martinez PP, Ke R, Mirza A, Conte M, Gallagher N, Conte A, Wang L, Fredrickson R, Edmonson DC, Baughman ME, Chiu KK, Choi H, Jensen TW, Scardina KR, Bradley S, Gloss SL, Reinhart C, Yedetore J, Owens AN, Broach J, Barton B, Lazar P, Henness D, Young T, Dunnett A, Robinson ML, Mostafa HH, Pekosz A, Manabe YC, Heetderks WJ, McManus DD, Brooke CB. Longitudinal assessment of diagnostic test performance over the course of acute SARS-CoV-2 infection. J Infect Dis. 2021 Jun 30:jiab337. doi: 10.1093/infdis/jiab337. Epub ahead of print. PMID: 34191025. Link to article on publisher's site

Journal/Book/Conference Title

The Journal of infectious diseases


This article is based on a previously available preprint in medRxiv.

Full author list omitted for brevity. For the full list of authors, see article.

Related Resources

Link to Article in PubMed

PubMed ID


Available for download on Thursday, June 30, 2022