The nationwide attention that has focused on the liver transplant operation here for Candice (Candi) Thomas, of Accokeek, Md., has spurred a nine-fold increase in calls to a national organ donor registry, officials there said today.

The Living Bank in Houston, Tex., which usually logs no more than 350 calls each week, received 3,000 calls this week from people seeking information and offering organs for transplant, according to spokesman Herma Breeden. Another employe said the registry even received calls from people offering their own livers because they didn't realize the organ could be taken only from an individual who had died.

Meanwhile, 16-month-old Candi remained in critical but stable condition today, which is normal following a transplant surgery, according to a spokesman here at Children's Hospital, the home of a famed transplant unit.

Candi's parents, Stewart and Penny Thomas, said their blond-haired, blue-eyed daughter was awake and alert today and that some intravenous tubes through which she had been fed had been removed.

"Did I tell you I got to feed her," an excited Stewart Thomas told a reporter. "I gave her a cherry popsicle."

The physicians completed Candi's ten-hour transplant operation early Thursday, just five days after President Reagan had made a personal appeal for a donor in his Saturday radio message.

The appeal by the president for Candi and another child has focused new attention on the nationwide problem of lack of donors and the high cost of the transplant surgery.

Today in Washington, a Baltimore man whose 2-year-old son is expected to die without a liver transplant, went before a congressional committee and pleaded for a national program directed by the federal government to gather and distribute organs.

"It's silly for a government of this magnitude and power not to address itself to this problem," said John Turpin Jr., testifying before a subcommittee of the House Energy and Commerce Committee. "Please cut the bureaucracy and get to work."

He and his wife, Marian, holding their ailing son, John III, told the panel they felt their time was running out. "Our worst fear," said Marian Turpin "is waiting till the last minute and knowing he may die because we did not extend our efforts."

Witnesses also testified that Medicare and most private insurers consider transplants experimental and will not pay for them. If Medicare would begin paying for those operations, some witnesses said, private insurers would follow that lead.

The president's appeal on behalf of Candi last week raised new questions about how institutions maintain their lists of children in need of transplants and how the donated organs are matched with the patients.

"We must avoid the chaos and bitterness that inevitably will arise if transplants are available only to the very rich or to those fortunate enough to be singled out by the media for special attention," said Rep. Henry A. Waxman (D-Calif.), chairman of the congressional panel.

However, agencies that procure donated organs said today that the president's radio message did not give Candi any particular advantage over other children waiting for livers.

University of Pittsburgh Health Center spokesman David Phillips said that no one at the university favors one patient in need of a liver over another.

He explained that potential liver recipients are evaluated at the hospital and put on a list. Then, when a registry refers a donated organ, it is matched according to size, blood and tissue type with the most critical patient on that list.

"If we can't use it, we refer it the liver to the next transplant center," Phillips said. The University of Minnesota Hospital and the University of Tennessee Hospital, the other major liver transplant centers, follow similar procedures, according to spokesman there.