About one-third of those people who tried to buy insurance on the private market were denied coverage because of a pre-existing condition over the last three years, a government analysis found.

How insurance companies handle pre-existing conditions has been a focal point in the debate over health care reform in the U.S., with President Barack Obama saying that any reform proposal crossing his desk must prohibit refusing coverage based on a person’s medical history or health risk if he is to sign it.

The report, “Coverage Denied: How the Current Health Insurance System Leaves Millions Behind” from the U.S. Department of Health and Human Services, appears to lend government support to Obama’s complaints about health carriers’ handling of these conditions and rescissions.

The report examined “the insurance company practice of denying coverage to or discriminating against Americans who have pre-existing medical conditions,” according to a statement from HHS.

Among 12.6 million non-elderly adults, 36% of those who tried to buy insurance on the private market “were discriminated against in the past three years because an insurance company deemed them ineligible for coverage because of a pre-existing condition, charged them a higher premium, or refused to cover their condition,” according to HHS. Another survey found 1 in 10 people with cancer said they could not get health coverage, and 6% said they lost their coverage because of their diagnosis, HHS said.

The analysis found that denying coverage because of pre-existing conditions is not confined to serious diseases. “Even minor problems such as hay fever could trigger prohibitive responses,” the HHS said. “An insurer could charge high premiums, deny coverage, or set a restriction such as denying any respiratory disease coverage to a person with hay fever,” according to the report.

Some insurance companies “respond to an expensive condition such as cancer by initiating a thorough review of the patient’s health insurance application,” the report also noted.

“If the company discovers that any medical condition, regardless of how minor, was not reported on the application, it could revoke coverage retroactively for the patient and possibly all members of the patient’s family,” the report said. The practice is known as rescission.

The authors note “companies can do this even if the condition found is not related to the expensive condition or if the person wasn’t aware of the condition at the time.”

The report said at least one company encouraged employees to revoke sick people’s health coverage through rescissions.