Dr. Garner added that the news should be taken with a note of caution. In recent months, several experts have called for more widespread at-home testing as a way to help curb the virus’s spread. But others have raised concerns about the practicality of a strategy that would most likely rely on tests that sacrifice a degree of accuracy for convenience and a more affordable price tag.
According to the product’s instructions, Lucira’s LAMP test was able to accurately detect 94.1 percent of the infections found by a well-established P.C.R.-based test. It also correctly identified 98 percent of the healthy, uninfected people. The study, which was conducted by the company, was small, and included only people who had symptoms of Covid-19, the disease caused by the coronavirus. The packaging for the test notes that it “has not been evaluated” in asymptomatic people.
Confused by the terms about coronavirus testing? Let us help:
- Antibody: A protein produced by the immune system that can recognize and attach precisely to specific kinds of viruses, bacteria, or other invaders.
- Antibody test/serology test: A test that detects antibodies specific to the coronavirus. Antibodies begin to appear in the blood about a week after the coronavirus has infected the body. Because antibodies take so long to develop, an antibody test can’t reliably diagnose an ongoing infection. But it can identify people who have been exposed to the coronavirus in the past.
- Antigen test: This test detects bits of coronavirus proteins called antigens. Antigen tests are fast, taking as little as five minutes, but are less accurate than tests that detect genetic material from the virus.
- Coronavirus: Any virus that belongs to the Orthocoronavirinae family of viruses. The coronavirus that causes Covid-19 is known as SARS-CoV-2.
- Covid-19: The disease caused by the new coronavirus. The name is short for coronavirus disease 2019.
- Isolation and quarantine: Isolation is the separation of people who know they are sick with a contagious disease from those who are not sick. Quarantine refers to restricting the movement of people who have been exposed to a virus.
- Nasopharyngeal swab: A long, flexible stick, tipped with a soft swab, that is inserted deep into the nose to get samples from the space where the nasal cavity meets the throat. Samples for coronavirus tests can also be collected with swabs that do not go as deep into the nose — sometimes called nasal swabs — or oral or throat swabs.
- Polymerase Chain Reaction (PCR): Scientists use PCR to make millions of copies of genetic material in a sample. Tests that use PCR enable researchers to detect the coronavirus even when it is scarce.
- Viral load: The amount of virus in a person’s body. In people infected by the coronavirus, the viral load may peak before they start to show symptoms, if symptoms appear at all.
Although the company has yet to release more detailed results on its product’s performance, “the data look good” and could enable the test to fill an important gap, said Susan Butler-Wu, a clinical microbiologist at the University of Southern California. One of the most serious issues bedeviling efforts to identify people infected by the coronavirus is the inconsistent access to reliable laboratory testing in many parts of the country, especially outside urban centers.
“This type of assay can play a big role there,” Dr. Butler-Wu said.
Representatives at Lucira Health did not respond immediately to requests for comment.
Saskia Popescu, an infection prevention expert and epidemiologist at George Mason University, cautioned that home testing, while a notable advance, is not a panacea. “No test is perfect,” she said, and a negative result should not be taken as a free pass to mingle. Moreover, testing alone cannot prevent the spread of disease, and must be combined with other public health measures like physical distancing and masking, she added.
Dr. Popescu also expressed concern at the vagueness around reporting results. At-home testing adds another degree of separation to the reporting process, which would need to include communications between patients and their health care providers, then a follow-up between those health care providers and public health officials.
The merits and pitfalls of at-home testing should continue to be weighed, Dr. Popescu said, adding: “We need more accessible and fast lab-based testing.”
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