What is the best way to find out if i am lactose intolerant? is there a test that can be done?

Blood and breath: Hydrogen breath test:breathing into balloon-type container after drinking flavored liquid containing lactose. Samples of breath collected at set time periods and hydrogen levels checked.Normally, little hydrogen.Unless body has trouble breaking down and absorbing lactose.Blood lactose tolerance test:body creates glucose when lactose breaks down.Ingest lactose solution and blood samples checked.