How Soon Can Marijuana Be Detected In The Body?

I haven t smoked marijuana in 53 days. I was an average smoker for almost a year. I m 6 2 163lbs. I just took a drug screen through quest diagnostics, and within about 6 hours they called and left a message saying they were calling in regard to my u.a. results. Take I m mind I took it at a physician s office and they were to send it to quest, who jas a lab in my city. I read on there site that it takes at least 24 hours for results, and in case of a positive result additional testing would need to be done adding at least another 24-48 hours. So what do you make of this?