The condition report on Rep. Gladys N. Spellman, still in a semicoma at Prince George's General Hospital but breathing without the aid of a respirator, was changed yesterday from critical to serious.

"That means she's stable," explained Jane Olson, hospital spokeswoman, who declined to elaborate further on Spellman's changed status. "There are no set criteria -- it varies from doctor to doctor," she said.

The 62-year-old Prince George's County Democrat suffered cardiac arrest last Friday while campaigning in a Laurel shopping mall. Since then, she has failed to emerge from a light unconsciousness, of what doctors have called "a sleep-like state."

"We've been saying all along there is steady progress, improvement each day," said Art Jaeger, a Spellman aide."There is a little more movement each day."

Spellman, reelected to the U.S. House of Representatives Tuesday by a landslide despite her critical condition, was moved to Prince George's General Wednesday from the Greater Laurel-Beltsville coronary care unit to undergo extensive neurological testing.

Those tests, designed to determine whether Spellman suffered brain damage, began yesterday, according to Olson. "We will not be releasing any information about the tests," she said.

Furthermore, she said, the testing may have to be conducted over a long period. "She has the type of illness that varies from person to person," she said. "We just have to wait and see."