(CNN) - Just a fraction of the more than 6 million people the Obama administration has touted as being determined eligible for Medicaid under Obamacare are new enrollees, according to an independent study released Wednesday.
The new study, published by the health advisory company Avalere, estimates that between 1.1 and 1.8 million people are newly enrolled in Medicaid thanks to the Affordable Care Act over the final three months of 2013.
While federal officials have frequently cited increased Medicaid enrollment as an example of Obamacare's success, they have been unable to report how many of those enrollees would have been eligible for the government program without the law's expanded eligibility requirements.
"Three million people have signed up for private plans in the Marketplace and more than 6 million learned they were eligible for Medicaid and CHIP, including new determinations in states expanding coverage as well as those made based on prior law and renewals," Health and Human Services spokeswoman Joanne Peters said.
When citing the latest enrollment figures, federal officials are often careful to note that the government's Medicaid figures include both new enrollments and renewals, but that hasn't stopped President Obama from using the combined figure as evidence of the law's effectiveness.
"Already, because of the Affordable Care Act, more than 3 million Americans under age 26 have gained coverage under their parents' plans," Obama said in his State of the Union address last month. "More than 9 million Americans have signed up for private health insurance or Medicaid coverage."
An HHS official confirmed that 6 million refers to the number of people who have been determined eligible for Medicaid since open enrollment began on October 1, not how many people have gained coverage they didn't have before.
"You really have to go through all the footnotes and all the qualifiers," said health law expert and Washington and Lee University law professor Timothy Jost on the search for more precise data.
"It isn't 6 million people who are new but there are a lot of new people. They're mostly in the expansion states and the number would be a lot higher if states like Florida and Texas, who have high numbers of uninsured, had gotten into the [Medicaid expansion] program."
Avalere found that roughly 75 percent of new Medicaid enrollment occurred in the states that chose to expand the program as allowed under the new law. To date, 25 states plus the District of Columbia have chosen to expand Medicaid eligibility.
By comparing the number of Medicaid applications over the first three months of Obamacare's open-enrollment period to the number of applications over the prior three months, Avalere found that on average the number of Medicaid applications increased by 12 percent. In states that expanded their Medicaid program, applications increased by 19.
In non-expansion states, "we're going to see a lot of people finding out they're too poor to get health care," Jost said, adding that the Medicaid enrollment numbers are still likely to "grow rather quickly."
One reason is that unlike with private insurance, Medicaid applications are accepted year round.
"If the increased rate of enrollment continues, we could see Medicaid rolls grow substantially throughout 2014," said Avalere Executive Vice President Matt Eyles in a statement accompanying the study.