Is this right? On erowid I found a chart on half-life times for pills. It got me thinking. A xanax's half life is 6-20 hours. Erring on the side of caution lets go with 20hrs. Better yet we'll say one day. So in: 2 days 1mg would be at .5mg, 3 days .25, 4 days .125, 5 days .0625, 6 days .03125-- on the 7th day the amount would be .015625-- thats .015,625,000 ngs (aint it?) A 180lb. man is apprx. 80 liters H2O--thats 80,000 mls. so 15625000ngs divide by 80,000mls is 195 nanograms per millilitre? Immunoassays can detect 200ngs per ml. of piss so yer clean in 7 days? Or have I been on drugs too long?