For years now, Kansas officials have assumed that between 10 percent and 14 percent of the state’s under-65 population lacks health insurance.

But a national survey released Wednesday pushed the Kansas number to 26 percent, or about one out of every four people.

The national average was worse, almost one in three.

“This is an epidemic that requires immediate attention,” said Ron Pollack, executive director at Families USA, a nonpartisan, Washington, D.C.-based advocacy group that promotes making health insurance available to all Americans.

In the past, Pollack explained, the number of uninsured was based on census data that measured how many people had been without insurance for at least a year. The process, he said, did not include those who, for example, had been uninsured for three, six or nine months.

When these numbers are added in, he said, each state’s percentage of uninsured increased.

Pollack defended the new numbers, arguing that someone without health insurance for nine months was likely to be as vulnerable as someone who was uninsured for 12 months.

Also, the data showed that of the 81.8 million children and adults who lacked health insurance in 2002 and 2003, 65 percent had been uninsured for at least six months. More than half had been uninsured for nine or more months.

Kansas fared relatively well in the survey. Only seven states — Delaware, Iowa, Massachusetts, Minnesota, New Hampshire, Vermont and Wisconsin — had a lower percentage of uninsured.

But that may soon change, said Gov. Kathleen Sebelius, who participated in a Families USA-sponsored news conference Wednesday in Washington.

Sebelius warned that neither Congress nor the Bush administration planned to extend a one-time increase in Medicaid funding.

“In Kansas, we got an additional $90 million,” Sebelius said.

If the emergency aid is not renewed, she said, Kansas will be forced to cut its Medicaid budget.

Sebelius also complained that federal officials have slowed payments to the states in the wake of Medicare and Medicaid reform efforts.

“For us, these disputes involve tens of millions of dollars. The fact that they are unresolved puts us in a very precarious position,” said Sebelius, who was Kansas insurance commissioner before being elected governor in 2002.

If states are forced to cut Medicaid budgets, numbers of uninsured are sure to increase, she said.

Already, Kansas has the strictest eligibility level in the nation for Medicaid assistance. An adult recipient can earn no more than 35 percent of the federal poverty guideline to qualify for Medicaid under Kansas rules.

Sebelius did not dispute the Families USA survey’s findings. Neither did Sandy Praeger, who replaced Sebelius as insurance commissioner.

“The overall message is that the problem is getting worse,” Praeger said. “I don’t know anybody who’s going to argue that.”

But Nikki King, executive director at Health Care Access, a Lawrence health care clinic for the uninsured, questioned some of the Kansas findings.

“The number — 26 percent uninsured — does not surprise me. But I’m not alarmed,” King said.

King said she had not seen a major increase in the number of people who were chronically uninsured and tended to have more serious health problems. She said she thought the increased numbers found in the study probably stemmed from better counting of those who were temporarily uninsured.