Fairfax County schools significantly improved their scores on state achievement tests given this spring, according to preliminary data, as all major school districts in Northern Virginia reported better results.

About 46 of 202 Fairfax schools reached the state target on the Standards of Learning tests, compared with 13 schools in 1998, the first year the tests were given, said Fairfax County School Superintendent Daniel A. Domenech.

"We are very happy with the gains we have made," he said.

Domenech said he could not be sure of the number of schools reaching the state targets until he receives more data from the state, expected later this week. He said preliminary results indicate 81 percent of fifth-graders and 73 percent of third-graders in Fairfax passed Standards of Learning reading tests, while fifth-grade history scores were still low.

Fairfax and Stafford County school officials said they hoped to release school-by-school results next week. Improved scores have been reported already in Alexandria. Prince William and Arlington counties indicated they will release favorable results tomorrow. The Loudoun school district has not set a date for releasing its data. Fauquier County school officials said they expect to release their scores in September and have not analyzed the results.

When last year's test results were released in January, many educators and parents were stunned to hear that less that 3 percent of the state's more than 1,800 public schools had reached the state targets. All schools that do not make the grade--defined generally as having at least 70 percent of students pass the tests--will lose their state accreditation in 2007 under rules approved two years ago.

The tests, part of a controversial effort to raise educational standards, cover basic subjects and are given each year to students in grades 3, 5 and 8 and in high school. Starting in 2004, any student who has not passed the high school examinations will not receive a diploma.

Officials who have seen the new test results said social studies is still a stumbling block for many schools. Officials in Fairfax and Arlington said more of their schools would have achieved the state benchmarks if they had reached the 70 percent level in social studies.

Cameron Harris, assistant state superintendent for assessment and reporting, said some officials have told her that the social studies scores lag behind those in English, mathematics and science. She said a new 600-page teachers resource guide is being distributed to help teachers see what is being covered in the history and government sections of the new tests.

State school board member Mark C. Christie said Virginia's learning standards--detailed in a 101-page book released in 1995--demand more new material in the state's social studies curriculums than in any other subject. "History has been a concern from the beginning," Christie said. But, he added, the statewide history scores are going up as teachers become more familiar with the new material--such as ancient China and Egypt for second-graders.

Domenech said the social studies tests "in many cases are just asking them obscure facts, and that is going to continue to be a problem." He said he hoped the state school board committees studying possible improvements in the tests will consider "dealing more with important concepts."

Fairfax County School Board member Mark H. Emery (At Large) said he hoped the results "would reduce some anxiety, but I still think there are some concerns," particularly in social studies.

Gary A. Reese (Sully), also a Fairfax board member, said he was "a little disappointed" in the county results. "I think at this point you begin to put aside criticism of the test and begin to aggressively underscore the need to improve the curriculum."

A Washington Post analysis of the first round of scores showed that schools with large numbers of low-income students usually had the lowest Standards of Learning scores. Relatively affluent suburbs such as Northern Virginia did better than low-income urban and rural parts of the state.

Staff writer Liz Seymour contributed to this report.