Clive Carter, who is is accused of murdering Khanokporn Satjawat in the women's toilets at the SECC complex on November 12 last year, appeared at the High Court in Glasgow for a preliminary hearing.
Carter pleaded guilty to the reduced charge of culpable homicide on his behalf, on the grounds of diminished responsibility. A second hearing will take place in August.
Satjawat, 42, died while attending a conference for HIV drug therapies at the Armadillo. Carter, of Lanarkshire, is believed to have been working as a G4S security guard during the conference.
Prosecutors allege Carter repeatedly struck Satjawat on the head and body with a fire extinguisher. The 35 year-old faces a further charge that he attempted to defeat the ends of justice to avoid arrest. It is claimed he cleaned blood and hair from the alleged murder weapon in a glass washing room within the venue.