An Upper Marlboro woman who was denied a secretary's job with Prince George's County in 1972 despite her qualifications has filed a class action suit against the county charging racial discrimination.

Patricia B. Allen had previously filed a complaint against the county with the Equal Employment Opportunity Commission, which ruled that there was "reasonable cause to believe" that Allen was discriminated against by the county, according to court papers.

If Allen's case is successful, as a class action, it could affect all blacks who were denied employment with the county after July, 1965, when the Civil Rights Act became effective, if these individuals can prove they were discriminated against.

The suit says Allen passed the two required tests for a secretarial job with the county and was informed by county personnel officials that she was "eligible" for the job.

She contacted the county three times in a year and was told there were no vacancies, the suit says, "although Prince George's County did have vacancies, in secretarial positions during that period . . . and these positions were filled by whites whose qualifications were inferior to Miss Allen's."

Prince George's county attorney James Chapin reserved comment on the suit until he had time to review it.