You can’t catch what you don’t see. New Yorkers will remember how this saying defined the early weeks of the city’s COVID-19 pandemic, as the boroughs and the nation struggled to develop a test for the virus. Delayed or absent detection meant people showed up to hospitals with their symptoms too far advanced, raging and beyond recuperation.

Laboratory testing gradually built itself up and evolved to cope with case surges, but it is now entering a new evolutionary phase with omicron. The highly transmissible variant has propelled the use of at-home COVID-19 tests, especially when lines for in-person tests were hours long or difficult to book around the holiday season. The U.S. Postal Service will now deliver kits to your door — if you can bypass the kinks in its ordering website. Supplies have improved online and at retail stores after deep shortages. And New York City schools are handing out millions of kits to exposed students and staff as well as symptomatic people who don’t want to stand in lines during this frigid winter.

But city officials are not tracking the results of the at-home tests, unlike other counties in New York and other major cities such as Washington D.C. and Austin, Texas. As Gothamist reported last week, this rise of the home kit is contributing to the sharpest drop in conventional testing that New York City has experienced during the pandemic.

As community transmission cools off, testing numbers tend to fall, but never quite as fast as current data show. Some health experts worry this decline is part of a larger national pattern with coronavirus testing, one that could make it harder to spot new variants.

Yet this winter, other jurisdictions such as Tompkins County in upstate New York potentially caught up to an extra 25% of cases by allowing their residents to report at-home test results. Translate these patterns to the five boroughs, and New York City could have spotted an additional 250,000 infections on top of the 1 million cases that have been recorded since it began handing out free home tests on December 16th. The same week, omicron became the dominant variant in the city.

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