Prince George's County's troubled Corrections Department, the target of a lawsuit charging jail overcrowding, fails to provide adequate medical care for inmates or adequate housing for prisoners in its work release program, according to a report released yesterday.

The Department of Audits and Investigations, an arm of the County Council, also said the Detention Center (jail) in Upper Marlboro lacks adequate means to collect information on its large inmate population. In a random check a year ago, the auditor found three conflicting totals.

The jail, designed to hold 143 prisoners, houses between 500 and 550 on an average day.

The report said the department has made considerable improvement in the overall management of the jail since control was transferred from the Sheriff's Department in 1978. It said the current corrections department director, Arnett Gaston, "has demonstrated considerable expertise in improving the functions of the detention center, and has worked to create an effective, efficient and fiscally sound organization."

The performance audit of the department was the first in nine years. Of about 60 recommendations made in 1973, the auditor found that 80 percent have been fully or partially implemented.

While praising Gaston's efforts, the report said:

* The department lacks adequate procedures for providing and documenting medical services for inmates and has inadequate staff -- four employes, who work 12-hour shifts -- for its medical unit.

* At the work release facility in Hyattsville, "four inmates would have to share each 6-foot-by-9-foot cell" if the facility were filled to its nominal capacity of 24 inmates (On an average, 12 live there). The washing machine, freezer compartment and stove "were broken or not available at all . . . We consider these conditions unacceptable," especially, said the report, since participants are expected to fix their own food and reimburse the county $5 a day for room and board.

Neither Gaston nor a corrections spokesman could be reached for comment.

In February, the county responded to a lawsuit filed by an inmate by agreeing to build a new jail, increase security personnel and upgrade conditions. Funds were obtained at the recent legislature session, The budget proposal pending before the County Council contains funds for more personnel. The inmate's suit still is pending, however.