I can not find a meme that asks how it is a different variant if they cannot test for a difference? I do not feel they would call it another Variant for fun.
If you get COVID-19, will you know it's the Delta variant? Here's why you likely won't (msn.com)
"We don't always know [the variant] when we do the regular tests," Winter said. "We do that in epidemiological studies ... "