World indoor 1,500 meters record holder Regina Jacobs of the United States has been banned for four years for a positive test for the anabolic steroid tetrahydrogestrinone (THG).

The United States Anti-Doping Agency (USADA) said in a statement on Saturday that Jacobs, 40, who announced her retirement on Thursday, had accepted the sanction after a positive test at last year's US trials, and will forfeit all her winnings since testing positive on June 21, 2003.

THG is at the center of the BALCO doping scandal that has engulfed US athletics.

An arbitration panel was scheduled to hear Jacobs's case on Sunday, the same day as the final of the US Olympic trials' women's 1,500 meters.

Jacobs, the 2003 world indoor 1,500 meters champion, was one of six US athletes entered in the trials facing doping charges.

World 100 meters record holder Tim Montgomery failed to finish in the top three, Olympic 400 meters silver medallist Alvin Harrison failed to make the final and his twin Calvin finished fifth.

Former world indoor 200 meters champion Michelle Collins withdrew from the trials. Olympic 4x100 metres relay gold medallist in 1996, Chryste Gaines failed to qualify for the 100 and later withdrew from the 200.