http://www.osti.gov/bridge/purl.cov...rug+retention+period&hl=en&ct=clnk&cd=1&gl=us I've decided to post this link regarding a study for drug retention in weekend users. There are plenty of answers and questions in this forum, and the internet is loaded with information. But one thing that is definitley lacking is information that has been put to an actual test about someone who does not normally use drugs, but takes a few on a weekend. Let's say this person is on parole or probation, forgot they had a drug test the following Tuesday or Wednesday, and is worried that because they took a few perscription pills or smoked a pipe on Saturday night or Sunday morning, they are going to fail an upcoming test. If this has happened or is happening to you, here's your study results. I copied the conclusive finds at the end for quick reference, but I recommend reading the entire results for peace of mind. This applies to the Standard 5 God bless "The effective detection periods show that a “Saturday night only” user (Scenario 1) would likely be identified in a drug test conducted the following Monday, with the possible exception of heroin and its metabolites. Effective detection of marijuana and phencyclidine could be accomplished during a longer detection period. A Friday and Saturday night user (Scenario 2) could be identifiable the following Monday at the latest except for heroin and its metabolites. If a drug test were conducted later, for example, on Wednesday or Thursday of the week following Friday and Saturday use, marijuana or phencyclidine are the only drugs that would likely be detected. It is possible that even regular users of marijuana may not be identified during routine testing after Thursday of a given week following use the pervious weekend. In the case of using a drug four times over the weekend (Scenario 3), all drug types would be detectable through the following Thursday except heroin and codeine, which would require testing by Monday and Tuesday, respectively. Due to longer retention times, the drugs (and metabolites) that would likely be detected for frequent users are marijuana and phencyclidine. Marijuana and phencyclidine could be detected for longer periods of time from eight days for phencyclidine to several weeks for marijuana as shown in Table 3"