If indeed Lindsay's drug test came back positive, the actress will have to serve 30 days in jail, according to the terms of her probation.
UPDATE: Lohan tweeted her own response: "Regrettably, I did in fact fail my most recent drug test and if I am asked, I am prepared to appear before Judge Fox next week as a result. Substance abuse is a disease, which unfortunately doesn't go away over night. I am working hard to overcome it and am taking positive steps. I am testing every single day and doing what I must do to prevent any mishaps in the future. This was certainly a setback for me but I am taking responsibility for my actions and I'm prepared to face the consequences. I am so thankful for the support of my fans, loved ones and immediate family, who understand that i am trying hard, but also that I am a work in progress, just as anyone else. I am keeping my faith, and I am hopeful....Thank you all!!!"