The document that qualified Michael Britt for admittance to the University of the District of Columbia was a forgery, D.C. School Supt. Vincent Reed said yesterday.

Britt, a 6-foot-7 freshman who led the Firebirds basketball team in scoring and rebounding, was dismissed from school last month because of alleged discrepancies involving his test scores on a high-school equivalency examination administered to him twice by the D. C. Public Schools.

He was dismissed because he did not meet entrance requirements, even though he earned a 2.6 grade-point average (C plus) in his first semester. UDC officials hold Britt "completely faultless" in the situation.

Orby Moss, athletic director at UDC, said yesterday that the document on which Britt was admitted was a transcript of his General Education Development tests and not a GED certificate, or diploma, as had originally been reported.

According to Moss, the transcript reported that Britt, from Suffolk High School, Suffolk, Va., had passed the five areas of examination satisfactorily and that a diploma had been issued. He said the transcript had the seal of the GED testing center in Washington and was signed by Alexander Hyman, chief examiner.

"It's not a true copy, let's put it that way," said Hyman.

Hyman said that a diploma, which must be signed by the superintendent and the president of the board of education, was never issued. Moss said that until notified by a reporter yesterday, he believed the document by which Britt was admitted was the GED certificate.

Moss, however, maintained the innocence of the athletic department. Wil Jones, UDC's basketball coach, could not be reached for comment. LaHugh Bankston, UDC's registrar and director of admissions, did not return a reporter's phone calls yesterday.

Moss said that the NCAA had not investigated the situation. He said the NCAA told him that the athletic department had violated no NCAA rules unless athletic department personnel were involved. "I've been satisfied from the first day of that," Moss said. Therefore, as of now, UDC will not forfeit any of the games in which Britt played "as long as we were not involved with the admissions foul-up," Moss said.

Britt said last week that he would make up classes in government and English, the two areas of the GED test in which he was unsatisfactory, and hoped to return to UDC in the fall.

Britt took two of the 2,496 GED tests administered by his office in 1979, Hyman said. He said that Britt had never passed the test and that he notified Reed of that the day after he read in the newspaper that Britt had scored more than 50 points in a UDC game.

"Some names tend to stick in your head," Hyman said when asked why he would remember the Britt tests specifically.

Hyman said it may well be true that his seal and his signature are on the document that was accepted by UDC. Hyman also said that only he has access to the seal and that it is kept under lock and key.

He said that he did not send a transcript to UDC. He added that students who fail the GED test generally do not ask that transcripts be sent out because colleges will not accept unsatisfactory scores.

"I've got no idea how they got it," Hyman said. "They've got a transcript of his scores and they did not come from this office."

"I don't know, either," replied Moss, when asked if he knew the source of the transcript. "If I knew how it came about, somebody would not be working now if he worked for me.

"The athletic department right now is as clean as any other in the nation. I will vouch for that. If not, I should be out looking for another job. We aim for our basketball team to go as high as it can.And once we get there, we don't want it to crumble down from something we did along the way."

Moss said one of his top priorities in his 1 1/2 years as UDC's athletic director was reestablishing the school's credibility after a series of athletic irregularities involving Federal City College, one of the three schools merged into UDC two years ago.