INDEPENDENT TD Clare Daly says she had not eaten since lunch and then drank a hot whiskey, which resulted in her arrest on suspicion of drink-driving.
The drink-driving suspect was in the Dail yesterday sitting alongside her colleague, tax cheat Mick Wallace.
The former Socialist Party TD said if the test result on her urine sample proved to be over the limit, she would "accept the consequences and resolve that this will not happen again".
Ms Daly should know by the end of next week whether she was over the statutory limit.
Analysis of urine samples takes on average between eight and 12 days.
If the result for alcohol is below the level of 107mg of alcohol per 100ml of urine, further analysis will be carried out routinely on the sample for other intoxicants.
Penalties on conviction for drink driving vary, depending on the amount of alcohol that has been detected in the system.
Ms Daly has been at the forefront of a high-profile campaign highlighting the alleged quashing of penalty points for motorists by garda officers.
If Ms Daly is found to be only marginally above the limit, she will not have to go to court but will, ironically, collect three penalty points and a €200 fine.
In a statement, Ms Daly gave further details of her arrest on suspicion on drink-driving.
She outlined how she went from north Co Dublin to the southside of the city, where she had the drink. She was stopped by gardai on her way home.
"On Monday evening after meetings in the Dail, I attended a meeting in Swords and left at 9.30pm for another meeting requested by a family of longstanding political acquaintances in the southside of the city near the canal.
"I arrived after 10pm and spent almost two hours discussing political issues. Before I left I was offered a hot whiskey for a cold. I had no food since lunchtime and did not realise the implications of taking this house measure of hot whiskey," she said.
Ms Daly also gave an explanation of how she ended up taking an illegal turn on the road, which resulted in the gardai pulling her over.
"I left at midnight and not being familiar with the area, found myself on the road to Ballyfermot at Kilmainham and took a right turn on to the South Circular Road trying to get back on to the northside – unfortunately there is no right turn at this junction.
"A passing garda patrol car saw the turn and pulled me over and this was brought to my attention by gardai in a car who stopped me. I was breathalysed but this was not satisfactory and was brought to the Kilmainham garda station where a urine sample was taken."
Ms Daly says she accepts responsibility for her actions, but complained about her arrest being leaked for drink-driving.
"I accept full responsibility for what is a serious lack of judgment and while I find it surprising that the gardai in Kilmainham released this information to tabloid journalists before 11am, I believe that the gardai implementing road safety have a job to do and I support them."