As America's record Omicron surge continues, cities and states across the country have no cohesive strategy to monitor the results of at-home rapid COVID tests.

Why it matters: This patchwork system means the official COVID case counts are almost certainly a vast undercount. Many cities don't have an accurate sense of just how prevalent COVID is as they make decisions about mask mandates, school closures and other restrictions.

One of the better systems is run by Washington, D.C., where the city has established a portal to report positives from an at-home rapid test, allowing a contact tracer to get in touch.

• The state of Colorado has a similar portal, and the city of Austin, Texas, has an email address to report at-home positives.

Yes, but: Residents don't always know about these options, and because they're all ad hoc systems, they can be difficult to track down even for the people who are inclined to use them.

• That's exemplified by a place like the Dallas-Fort Worth metroplex, where Fort Worth's Tarrant County has an extensive self-reporting tool while Dallas County simply refers back to the CDC's general guidance on at-home testing.
• There's also no requirement to report an at-home positive result, even if the service is available.
• And many people may not even realize that they have the option at all.

The other side: Many areas simply don't have a system in place at all. "It is my perception that there is an understanding that cases are indeed higher because some people are testing positive using home kits," said Jessica Corbitt, a spokesperson for Georgia's Fulton County, which contains most of Atlanta.

• Chicago says that at-home tests are a helpful diagnostic tool, but they "are not included in official COVID-19 case counts."
• In Des Moines, the Polk County Health Department only counts cases verified using a PCR test.
• In the Twin Cities, the Minnesota Department of Health cites the lack of "a good way to verify the results" as its basis for not tracking at-home results.

What they're saying: Minnesota Department of Health spokesman Doug Schultz told Axios that the state's reasoning on at-home tests is based on the fact that "we don’t have complete case ascertainment now."

• "We may not be able to count every case, but people will continue to get laboratory-run testing, so our data will still provide a picture of what is happening in the state," Schultz added.
• North Carolina has a similar take. "There are going to be more cases out there than are reflective in our data. What we’re really interested in is our hospitalization data. That’s our key focus right now," said Dr. Susan Kansagra, acting senior deputy director for the state's Division of Public Health.

The big picture: Rapid tests are already in short supply, and a small preprint study released this week found that people may not test positive with them until after they're infectious, which would make them an unreliable measure of whether it's safe to gather, as Axios' Caitlin Owens reported.

• "Based on viral load and transmissions confirmed through epidemiological investigation, most Omicron cases were infectious for several days before being detectable by rapid antigen tests," the study's authors wrote.

The bottom line: Omicron may have exposed the limitations of at-home rapid tests — not only as a gauge of how big the current case surge truly is, but also as a possible pathway to avoid COVID disruptions in daily life.

Axios' Chelsea Cirruzzo, Jason Clayworth, Katie Peralta Soloff, Asher Price, Torey Van Oot and Thomas Wheatley contributed to this report.

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