The Iowa Poll conducted by Selzer & Company for the Des Moines Register, CNN and Mediacom recently shook up the Democratic primary field.

The Selzer poll — which was alone amongst pollsters in its accurate prediction of then-Sen. Barack Obama’s easy win in the caucus in 2008 — found Sen. Elizabeth Warren, D-Mass., apparently leading among likely Iowa Democratic caucus-goers for the first time. Warren holds a two percent lead of 22-20 over former Vice President Joe Biden. Biden led the field in all previous Selzer polls this cycle.

Warren’s lead is within the poll’s four percent margin of error, though those top two candidates lead the third place candidate, Sen. Bernie Sanders, I-Vt, by a margin well outside the poll’s margin of error. Sanders has the support of 11 percent of likely caucus-goers.

J. Ann Selzer, president of Selzer & Co., said this poll is a major shakeup, the Des Moines Register reported.

“It’s the first time we’ve had someone other than Joe Biden at the top of the leaderboard,” Selzer said.

Sanders nearly won the Iowa Democratic Caucus in 2016, receiving 49.6 percent to eventual nominee Hillary Clinton’s 49.9 percent. The poll further found he is losing to Warren among those who caucused for him in 2016. Sanders is holding onto only 25 percent of his 2016 supporters while Warren is pulling in 32 percent. Furthermore, the poll finds that Sanders has the support of zero percent of those who caucused for Clinton in 2016, in line with the 1 percent support from Clinton supporters an Iowa State/Civics poll found.

When asked about the new poll by an ABC reporter, Sanders said his campaign’s data showed a “very different situation” in Iowa.

“[B]ottom line, I think we’re gonna win here in Iowa,” Sanders said.

Warren declined to react to the poll, responding when asked about it with “I don’t do polls.”

The poll could portend trouble for some lower polling candidates hoping to remain contenders in the race. The Democratic National Committee (DNC) unveiled new qualification criteria for its November presidential debate Monday.

In order to qualify, a candidate must receive at least three percent in four DNC approved polls of either Iowa, New Hampshire, Nevada, South Carolina or nationally or five percent in two separate DNC approved polls of a single one of the aforementioned states with a reception of at least 165,000 unique donations from at least 600 unique donors in at least 20 different states. Candidates have until a week before the November debate to fulfill the qualification criteria.

No candidates other than Warren, Biden or Sanders currently have double digit support among likely Iowa caucus-goers; South Bend Mayor Pete Buttigieg, D-Ind., holds nine percent support, Sen. Kamala Harris, D-Calif., has six percent support, and Sen. Cory Booker, D-N.J., has three percent support alongside Sen. Amy Klobuchar, D-Minn. No other candidate is above two percent in the poll.