Discard Tubes for Factor Assays

Donald R. Peven, MD, of Pontiac, MI extends the question of discard tubes to their use for factor assays. He writes… 
What is the current practice concerning drawing a waste tube before coag specimens when doing venipuncture? Our understanding is that the NCCLS (CLSI) guideline says that it is OK to draw PTs and PTTs without a waste tube, but if other coag assays will be run there needs to be a waste tube drawn. Is there a change in this practice anticipated with the new guideline coming out?