Gov. Mike DeWine of Ohio Tests Positive for Coronavirus on Way to Meet Trump

Gov. Mike DeWine tested negative for the coronavirus hours after a positive rapid-result test had prevented him from welcoming President Trump to Ohio on Thursday, a whiplash reversal that reflected the nation’s increasingly complex state of testing.

In a high-profile example of a new testing frontier, Mr. DeWine first received an antigen test, which allows for results in minutes, not days, but has been shown to be less accurate. The positive result came as a “big surprise,” said Mr. DeWine, a Republican, who had not been experiencing symptoms other than a headache.

Later on Thursday, he was tested using a more standard procedure known as polymerase chain reaction, or P.C.R., an accurate but time-intensive method that requires samples to be processed at a laboratory. His wife, Fran, and staff members also tested negative.

“We feel confident in the results,” the governor’s office said in a statement late Thursday, noting that the negative result had been processed twice. “This is the same P.C.R. test that has been used over 1.6 million times in Ohio by hospitals and labs all over the state.”

The puzzling results capped a long day for Mr. DeWine, 73, who drove three hours up Interstate 71 to meet with Mr. Trump in Cleveland. He had hoped to discuss testing, a key issue that has plagued the response to the virus in the United States. But first, he had to be tested himself as part of a routine White House screening.

After the unwelcome news, the president stood alone outside Marine One and praised Mr. DeWine as “a very good friend of mine,” while Mr. DeWine left to get the secondary test and returned to quarantine at his home in Cedarville, Ohio.

Several people have tested positive as part of regular screenings meant to protect the president, including Representative Louie Gohmert, a Texas Republican who has frequently refused to don a face covering in the Capitol. Campaign staff members who attended the president’s rally in Tulsa, Okla., in June also tested positive.

The immediate result Mr. DeWine received during the White House screening stands in contrast to the experience of many Americans, who have had to wait hours to be tested for the virus and continue to face turnaround times that stretch for days and even weeks.

Public health experts say that widespread, rapid testing is necessary for quarantining and contact tracing to effectively control the virus. But the United States has consistently struggled to test as frequently as needed. The country has recently averaged about 700,000 tests per day, nowhere near the millions of tests that some models recommend.

Experts are increasingly arguing that the best chance to catch the most outbreaks is through large numbers of less accurate tests. But there are drawbacks: Antigen tests will miss some people who would test positive by P.C.R., with some past antigen tests missing up to half the infections they looked for.

Mr. DeWine was the second governor to publicize a positive test, after Gov. Kevin Stitt of Oklahoma, a Republican, tested positive for the virus last month.

A mild-mannered career politician, Mr. DeWine spent decades in public office — as a county prosecutor, state senator, congressman, lieutenant governor, U.S. senator and state attorney general — largely out of the national spotlight, until the pandemic turned him into something of a social media sensation. At times breaking with his party to take a more assertive approach on public health, Mr. DeWine was the first governor to shut down schools, and he issued an early stay-at-home order in March.

His daily 2 p.m. news briefings, in which he took on a professorial air, speaking alongside graphs and charts while wearing round glasses and colorful ties representing Ohio universities, spawned a fan club this spring. The briefings, known as “Wine With DeWine,” inspired T-shirts and wine glasses with the motto “It’s 2 o’clock somewhere.”

But his approach also drew an uproar from protesters who gathered outside the State Capitol and from members of his own party. Amid the stay-at-home order and business closures, Republicans accused his administration of “micromanaging” residents and pumping up coronavirus statistics to scare Ohioans.

As new daily cases in Ohio surged this summer, ballooning to more than 1,000 a day, more than the state’s previous peak in April, Mr. DeWine again took on a more urgent tone. “Don’t we all want to be around to meet our future children, our future grandchildren?” he said during a televised state address last month. “To attend their baptism, to watch our kids and grandkids graduate from school?”

He later issued a statewide mask order, drawing familiar criticism. Before the governor’s negative test on Thursday, a Republican state representative, Nino Vitale, posted a photo of Mr. DeWine wearing a face covering with the news he had tested positive: “I thought masks worked?”

Mr. DeWine pushed back against critics on Thursday, saying he had received several “not so nice” text messages suggesting that wearing a face covering did not matter. “Look, we know it does,” he said.

Ohio is among eight states that this week made a bipartisan pact to buy four million antigen tests, with the hope of detecting outbreaks more quickly. The governors are negotiating to buy the tests from two medical companies — Becton, Dickinson & Company and the Quidel Corporation — whose tests could produce false negative results between 15 and 20 percent of the time.

Speaking to reporters after his positive test, Mr. DeWine said that he had considered the possibility of an inaccurate result but that that would not change his desire to pursue a variety of testing options for the state, including more rapid testing.

“It’s a constant re-evaluation,” he said. “Collectively, we know more about the virus today than we did in March. Same way with testing.”

Even so, the contradictory test results that the governor received show that there is considerable room for improvement. His office said that “out of an abundance of caution,” the governor would be tested again in two days.

Julie Bosman, Maggie Haberman and Nicholas Bogel-Burroughs contributed reporting.