SAN DIEGO -- Some summer-school F's may have been changed into passing grades at the prestigious Preuss School, where administrators are scrutinizing about 100 grades, it was reported Saturday.

Cecil Lytle, chairman of the Preuss board of directors and a founder of the university-affiliated public charter school overseen by the San Diego Unified School District, told the San Diego Union-Tribune an audit under way should be completed next month.

Auditors are trying to match grades on student transcripts against teachers' grade books.

One allegation is that students who did not attend summer school got credit for it, The Union-Tribune reported. Another allegation is that grades were mixed up, and students enrolled in certain courses were given grades in other courses, the newspaper reported.

So far, nothing suggests any wrongdoing by students. Still, some college- bound seniors at the 780-student charter school affiliated with UC San Diego worried that the investigation would cast doubt on their transcripts.

Others worried that bad publicity would hurt fundraising.

Preuss, recognized for preparing disadvantaged students for college, was ranked one of the top 10 high schools in the country by Newsweek. The Center for Education Reform named Preuss one of 53 National Charter Schools of the Year, the Union-Tribune reported.

Representatives from schools such as Princeton, Columbia, Duke and Harvey Mudd are scheduled to visit Preuss to recruit students in the coming month.