Two-thirds of the nation's 3.3 million elderly with incomes below the poverty line are not eligible for Medicaid, the federal-state medical program for the poor, the Commonwealth Fund, reported in Washington. An estimated 3.6 million of the 4.3 million "near poor" elderly also are ineligible, the report said. As a result, even if congressional plans for "catastrophic" health insurance are added to Medicare coverage, millions of low-income elderly will remain without adequate health coverage and face crushing out-of-pocket medical costs, the report predicted. The reason so few of the elderly poor and near poor are covered by Medicaid is that states are free to set income cutoffs for coverage. The report said the average cutoff level for a single person is 83% of the poverty line and for a couple 104%.