The National Naval Medical Center in Bethesda, the flagship hospital for the Navy and the facility where President Ronald Reagan was examined last week, is in danger of losing its national accreditation because of questions over its quality of care, hospital officials confirmed.

A survey team from the Joint Commission on Hospital Accreditation (JCAH), the nationwide medical facility surveying firm, made a tentative recommendation that approval for the Navy hospital be dropped, Navy officials said.

The world-famous hospital had been under a one-year, instead of the usual two-year, approval by the accrediting agency. The one-year approval was based on a survey conducted May 7, 1980. The agency used to call its one-year approvals a "probationary" term and it is imposed when there are a number of deficiencies, explained Sharon Hamilton, a program manager for JCAH.

The latest action is based on a second, three-day survey last November, where deficiencies were found in how the hospital documented the quality of care patients receive. The Chicago-based surveyors have specific standards to assure quality, such as requiring that actions of the medical staff be monitored.

"We probably were somewhat behind," Lt. Cmdr. Ronald Arrison, of the hospital's public relations staff, said of the JCAH requirements. "These areas have been corrected."

He stressed that the survey team's findings were tentative and noted that the hospital had been praised by the team for "providing quality health care for its beneficiaries."

If the hospital loses JCAH approval, it would no longer be eligible for the military's equivalent of Medicaid and Medicare reimbursement from the government and its extensive residency and internship programs for doctors and nurses would be placed in jeopardy.

Currently, the hospital trains 52 interns and 177 residents. If the facility is denied accreditation, Navy medical trainees would be sent to one of the service's three other training hospitals, in Portsmouth, Va., San Diego or Oakland, Calif., said Lt. Cmdr. Patricia Pallas, a public affairs officer for the Navy Department.

Losing accreditation also would be a blow to the hospital's reputation, since many doctors refuse to practice in nonaccredited institutions.

Top Navy officials, worried about the effect of their hospital's poor evaluation, met last week to determine how to overturn the JCAH's preliminary decision, reported Defense Week, a military trade journal. The journal said Adm. Thomas Hayward, the Chief of Naval Operations, urged Navy Surgeon General Vice Adm. William Cox, to try to change JCAH's mind when one of its committees meets April 16 to make a final decision on the Bethesda medical center.

JCAH is governed by five national organizations, including the American Medical Association, and provides voluntary accreditation services for more than 5,000 health care facilities throughout the country.

Only one percent of the hospitals seeking accreditation fail to achieve it, said Hamilton. About 79 percent of the hospitals that win approval receive two-year accreditation; the remainder receive one-year approvals.