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I'm going to visit family for Thanksgiving. Should I get a COVID test before I go?

To test or not to test?

As people consider Thanksgiving travel amid a fall surge in COVID-19 cases around the U.S., lines to get tests in some places have grown longer.

But should you get a COVID-19 diagnostic test if you're traveling home to visit loved ones, including older relatives?

Testing as close as possible to the time that you're traveling is helpful, medical experts say, but that doesn't mean that it's a sure way to prevent the spread. 

"We're in the middle of an unprecedented pandemic. We shouldn't sugar coat this with ways around doing what is the safest, which is not going," Dr. Cameron Wolfe, an infectious disease specialist at Duke University Hospital, wrote in an email to USA TODAY.

Here's what you need to consider as you decide whether to get tested and travel:

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A test is better than no test. But should you travel at all?

A more pertinent question may be whether traveling at all is best, the doctors agree.

Dr. Christopher Sanford, an associate professor of family medicine and global health at University of Washington, said that is an individual decision and will differ across family situations and medical histories.

However, "the truth is still the best way not spread this is to not be around people," he said. And, "this is advice that I wince as a give, because it's a little cruel to tell people not to socialize with their family and friends."

"We cannot test our way out of risk," Wolfe added. Every decision about if you should travel, when to get tested and what kind of test to get affects the balance of risk and reward in seeing family for Thanksgiving, but, "you have no increase in risk if you stay where you are," Wolfe said.

The Centers for Disease Control and Prevention on Thursday recommended against travel for Thanksgiving.

But ultimately, if your decision is to travel, getting a test is better than not, even if the lines and turnaround times are long. "It's much better than doing nothing," said Dr. William Greenough, an infectious diseases specialist at Johns Hopkins University.

Tests are a moment in time

A COVID-19 diagnostic test can show if you have an active coronavirus infection, according to the CDC, but a negative result "only means that you did not have COVID-19 at the time of testing."

"People need to recognize that a test today only proves you're OK today. It says nothing about whether you might be incubating, or exposed, and won't turn positive tomorrow or the next day," Wolfe said.

The average incubation period for COVID-19 is about five days, Sanford said, but it could take as long as 14 days to incubate.

If you see a friend who is infected on Sunday, you may not start getting sick until Friday — and a test on Monday may be negative, but you'll still potentially be spread the virus to your family while you're chatting and laughing and eating dinner on Thursday, he said.

It is also possible to be exposed after getting tested. For example, if you get a test then take a flight to visit family, you could be exposed on the plane. (Studies have painted a muddled picture about how safe airplane travel is.)

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Testing is not a replacement for social distancing

While a test can tell you if you're likely negative on a given day, it should not replace other measures like wearing a mask, staying 6 feet apart and social distancing, experts say.

"If you have been in any close group contact for the last two weeks, you should be quarantining for a two week period," Greenough said. "The test will not be the final arbiter until two weeks have passed."

A negative test result is "not a failsafe. It's not protective," added Sanford. "I do worry people think they are going to be safe if they get tested."

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While the risk is lower if someone is not traveling in a group and can actually maintain relatively safe distances from others, that becomes harder to do in the colder months, Wolfe said.

When to get tested if you are traveling

Getting a test and a result the day you are traveling would be ideal, Greenough said, but that is not always possible across the United States.

In some places, it can take four to five days to get test results, and getting a test five days before your trip is less representative than one the day before, Wolfe said.

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A rapid antigen test could tell someone within minutes of getting in the car to travel whether they are positive, but the tests are less accurate compared to molecular tests, Sanford said.

Another challenge is that testing likely won't detect an infection immediately after an exposure to the virus. Tests are "markedly less accurate" early on in the incubation period compared to a test on someone who is symptotic and a week in, he added.

Follow USA TODAY's Ryan Miller on Twitter @RyanW_Miller