Despite major expenditures, medical care in the District's juvenile detention facilities is "not only chronically poor but also constitutes gross medical incompetence," a report prepared for a court-appointed monitor said yesterday.

The 116-page report by Dr. Mark J. Wade, medical director of the Spofford Juvenile Center in the Bronx, N.Y., says medical records at Oak Hill, Cedar Knoll and the District's Juvenile Receiving Home are poorly kept and indicate "haphazard" treatment. Wade, who was paid about $15,000, examined the records and interviewed D.C. government medical personnel during a 12-day visit in September.

Although the doctors involved defend the care they provide, Marjorie Hall-Ellis, D.C. commissioner of social services, whose agency operates the detention facilities, said yesterday that Wade's conclusions are "the same things we discovered" since she took office about two months ago.

Hall-Ellis promised to appoint a medical director for the juvenile facilities, as the report recommended. The director would have clear authority to coordinate services, which the report said are fragmented. She said that she hired a consultant two weeks ago to draw up new procedures and that she has "put into action a plan which will correct each problem" mentioned by Wade.

But Hall-Ellis cautioned, "Don't come back next week and ask, 'Is it all fixed up and polished up?' Next week it won't be. But we are moving."

Wade was hired by Michael J. Lewis, a lawyer appointed by D.C. Superior Court Judge Ricardo M. Urbina to monitor a consent decree agreed to in July 1986 by the District government and lawyers for the American Civil Liberties Union and the D.C. Public Defender Service. The decree covers most aspects of the operation of the juvenile detention facilities, including medical care.

The report contains brief summaries of 54 case records picked at random by Wade. He said 38 of them show "poor medical documentation," inappropriate diagnosis, testing and treatment, or "overall poor medical management."

However, none of the case summaries indicates that patients had specific bad effects from medical care or that the D.C. goverment physicians missed a serious medical problem that should have been treated.

The detention facilities house an average of about 300 inmates a day with two physicians and two registered nurses who work full-day shifts, three other physicians on regular call, and a staff of physician assistants who provide round-the-clock service.

Wade said the District "has one of the largest, if not the largest, health care programs for confined juveniles in the country," with "more health care clinicians per juvenile population than most . . . other juvenile" prison systems.

Even though city financing is ample, physicians at the detention centers complained that they often did not have adequate supplies because the District government did not pay suppliers promptly. The report said there was an unspecified period when "soap, soap powder and deodorant were either not available or were being rationed due to low supply."