DUI No breathalyzer,Bloodwork...Urine sample with consent?

When testing for DUI do they test these 3 things. Is it true that Urine test can be inaccurate when it comes to alcohol ? But obvious when it comes to drugs. Would u fight a first offense dui if u are drug free but an occasional drinker ? I hear alcohol for urine can mean u drank the day before or it doesnt determine a limit or how much is consumed...Illuminate me please