UK residents are facing a conundrum, the Guardian reports, with lateral flow tests for those not showing symptoms no longer free of charge beginning April 1 in England and April 18 in Scotland.
"For months many of us have used a single red line in a plastic cartridge as a kind of social traffic light — swaying whether go out or stay at home to protect others from COVID," writes science correspondent Linda Geddes. But no longer.
The article offers a few points to guide testing decisions for individuals beginning to weigh cost versus benefit.
According to the Guardian, testing before visiting a vulnerable relative or other contact can reduce the risk of transmission, but doesn't entirely negate it. Lateral flow tests only turn positive above a certain threshold of virus in the body. "You can be infectious without noticing symptoms, or before symptoms develop, and lateral flow tests may miss this," Ajit Lalvani, chair of infectious diseases at Imperial College London, tells the Guardian.
Although they are better than nothing, people should be aware that LFTs could provide false reassurance. To further reduce risks, Lalvani advises other measures like ensuring that both parties are fully vaccinated, limiting other social exposure, washing hands, wearing masks, and meeting in a well-ventilated or outdoor area.
For people with suspicious symptoms, a positive LFT could confirm COVID-19 infection, but negative results, especially early after you get sick, don't necessarily mean you are virus-free.
Irene Petersen, a professor of epidemiology and health informatics at University College London, tells readers that they should stay home with any symptoms, and if LFTs are limited, "don't waste your test at the beginning – keep it until day two or three."
And for those recovering from a confirmed COVID-19 infection, NHS guidance says you should stay home for up to 10 days from when symptoms start. If you're willing to eat the cost and don't have a fever, a negative LFT result on days six and seven could get you back to business sooner.