Federal officials project that at least 450,000 Americans will have been diagnosed with AIDS by the end of 1993, according to published reports.

The estimate, reported in Sunday editions of The Washington Post and The New York Times, represents the first major revision in two years of the nation's projected AIDS caseload.The current cumulative total of AIDS victims is 63,726.

The new projections were presented last week to more than 150 senior health service officials who gathered at a private meeting in Charlottesville, Va., to plan a federal response to the AIDS epidemic, the newspapers reported.

The boldest proposal at the conference, according to several key participants interviewed by the Times, was a call by the drug abuse working group for a large increase in the quantity and quality of treatment programs for intravenous drug users.

According to drug abuse professionals who heard the panel's summation, the Times said, experts from the National Institute on Drug Abuse recommended that the number of slots in drug abuse treatment programs be boosted from the current level of 148,000 up to 380,000 to serve roughly a third of all the nation's drug abusers.