But dogged by issues of cost, access, logistics and employee privacy, tests aren't part of most back-to-work plans.(Photo: Shutterstock)

(Bloomberg) –From nursing homes in New York and a landfill in Utah to Disney World and the Las Vegas Strip, employers are wrestling with workplace safety in the age of Covid-19 and making fraught calculations about how to safeguard both their businesses and their employees. Mass testing, a critical tool to stem the virus's spread, would appear an obvious solution.

But dogged by issues of cost — diagnostic tests start at around $100 each — access, logistics and employee privacy, tests aren't part of most back-to-work plans. As health-care companies that work with employers in this capacity are fond of saying, there's no silver bullet.

Another major deterrent is that Covid-19 tests only measure that point in time, notes Lauren Vela, senior director for the Pacific Business Group on Health, which represents large employers like Microsoft Corp. and Walmart Inc. If a worker is infected shortly after being tested, it wouldn't show up but everyone would be falsely reassured by the negative result.