Written by: Apoorva Kakkilaya
Edited by: Esther Melamed
On November 17, 2020, the FDA issued its first emergency use authorization (EUA) for a self-test kit that can be administered entirely at home. The Lucira COVID-19 All-In-One Test Kit utilizes RT-LAMP technology to detect SARS-CoV-2 RNA from self-collected nasal swab samples. Swabs are placed in an included test unit and a positive or negative result is displayed within 30 minutes. Data from the manufacturer indicates sensitivity of 94.1% and specificity of 98.0%. Access to this test requires a prescription from a health care provider and is also authorized for point-of-care settings. Overall, this diagnostic test is a positive step forward in expanding accessibility of tests for SARS-CoV-2.
On another note, during this holiday season, it is especially important to keep in mind the limitations of diagnostic testing and the importance of following self-isolation guidelines if exposed to the virus. Although there are a plethora of tests available on the market, none of the tests currently test for infectiousness. This means that a negative test result isn’t guaranteed to preclude infectivity, and as a result, the timing from possible exposure at which one gets tested is important. According to research published in the Annals of Internal Medicine and cited on the CDC website, the median incubation period for the virus to replicate to detection levels is approximately 5 days and 97.5% of those who develop symptoms will do so within 11.5 days (Grantz et al. 2020). Furthermore, a literature review and pooled analysis of studies providing RT-PCR data by time of symptom onset reveals that there is a 67% likelihood of a false-negative test 4 days after exposure, with the rate dropping to 20% on day 8 (Kucirka et al. 2020). This further highlights the importance of understanding the incubation period for virus detection when interpreting test results to mitigate pre-symptomatic or asymptomatic spread.
References
Commissioner, O. (n.d.). Coronavirus (COVID-19) Update: FDA Authorizes First COVID-19 Test for Self-Testing at Home. Retrieved November 25, 2020, from https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-first-covid-19-test-self-testing-home?utm_medium=email
Kyra H. Grantz, Qifang Bi, Forrest K. Jones, et al. The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Annals of Internal Medicine 2020;172:577-582.
Stephen A. Lauer, Oliver Laeyendecker, Denali Boon, et al. Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction–Based SARS-CoV-2 Tests by Time Since Exposure. Annals of Internal Medicine 2020;173:262-267.
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