Some have braved hourslong lines at local testing sites to receive polymerase chain reaction tests, whose results, obtained in a laboratory, are considered the gold standard for detecting the virus. Many others have rushed to buy rapid at-home tests, depleting the stock at pharmacies and online stores. The frenzy for at-home testing has turned the kits into a commodity and even made them covetable holiday presents…

Some people have been stockpiling testing kits, citing concerns about the Omicron variant. Amber Decker, 45, a genetic genealogist in Columbus, Ohio, said that she originally started accumulating a small stockpile of tests ahead of a trip she and her friends were planning for January. “I wanted to be able to ask everyone to test without asking each person to spend money on tests,” she said. So whenever she saw testing kits on sale, she bought them.

Ms. Decker currently has 13 individual tests and just ordered eight more. “We have used home tests a handful of times in the past when we had worrisome symptoms, but with Omicron, it looks like we will probably need to be using them more often,” she said. But cost of the tests “really adds up,” Ms. Decker added.