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BACKGROUND: Testing individuals suspected of severe acute respiratory syndrome-like coronavirus 2 (SARS-CoV-2) infection is essential to reduce the spread of disease. The purpose of this retrospective study was to determine the false negativity rate of the LumiraDx SARS-CoV-2 Ag Test when utilized for testing individuals suspected of SARS-CoV-2 infection. METHODS: Concurrent swab samples were collected from patients suspected of SARS-CoV-2 infection by their healthcare provider within two different urgent care centers located in Easton, MA, USA and East Bridgewater, MA, USA. One swab was tested using the LumiraDx SARS-CoV-2 Ag Test. Negative results in patients considered at moderate to high risk of SARS-CoV-2 infection were confirmed at a regional reference laboratory by polymerase chain reaction (PCR) using the additional swab sample. The data included in this study was collected retrospectively as an analysis of routine clinical practice. RESULTS: From October 19, 2020 to January 3, 2021, a total of 2241 tests were performed using the LumiraDx SARS-CoV-2 Ag Test, with 549 (24.5%) testing positive and 1692 (75.5%) testing negative. A subset (800) of the samples rendering a negative LumiraDx SARS-CoV-2 Ag Test was also tested using a PCR-based test for SARS-CoV-2. Of this subset, 770 (96.3%) tested negative, and 30 (3.8%) tested positive. Negative results obtained with the LumiraDx SARS-CoV-2 Ag test demonstrated 96.3% agreement with PCR-based tests (CI 95%, 94.7-97.4%). A cycle threshold (CT) was available for 17 of the 30 specimens that yielded discordant results, with an average CT value of 31.2, an SD of 3.0, and a range of 25.2-36.3. CT was > 30.0 in 11/17 specimens (64.7%). CONCLUSIONS: This study demonstrates that the LumiraDx SARS-CoV-2 Ag Test had a low false-negative rate of 3.8% when used in a community-based setting.
RESUMO
Clinical laboratories are often faced with the decision to either perform a service in-house using their own assets or outsource the service to another vendor. This decision affects many aspects of the laboratory's business, from the macroeconomic perspective of outsourcing the laboratory service to a laboratory vendor, to the microeconomics of determining whether to refer a test out to their reference laboratory or perform the test in-house. The basis for decision making includes many variables, but a detailed financial analysis is usually the basis for the decision, especially when the decision only affects the laboratory and not the rest of the institution. Other factors often come into play, and depending on the magnitude, the "make versus buy" decision could be based more on strategic or political factors than economics. Even when noneconomic factors are involved, an effort usually is made to quantify those factors so that the make versus buy decision is reduced to financial terms. The previous article in this issue, "Effectively Managing Your Reference Laboratory Relationship" by Ronald L. Weiss, M.D., focused on the "buy" decision relating to managing the reference laboratory relationship. Although that article took a more clinical perspective through the eyes of the reference laboratory, this article looks at the make versus buy decision from a financial perspective through the eyes of the buying party.
