SMILLER, Thanks for the input...you know anyone can say anything on these forums so it is good to get references. If it makes you feel any better, my department had no deficiences at our last CAP inspection for what it is worth. CAP standard HEM.35850 says Two different levels of stabilized controls are analyzed and results recorded during each 24 hours of analyzer use. We also use XB and XM to ensure our instruments are running well. We have never had our QC go out. Once in a while a vial will go bad, but our QC is always right on. My husbands lab is JCAHO inspected and they are required to run QC every 8 hours. Funny that they are more strict! We do not run QC after a reagent change (see HEM.24575). When new reagents are put on, you have to do something...you can run QC if you wish (expensive), or you can run a patient you previously ran on the old lot. Again, the med director sets tolerance limits. For inert materials like diluent, you just have to run a background on the reagent lot number. We do this when the diluent comes in...check one background on one box to say the entire lot/delivery is QC OK. The med director sets tolerance limits for this as well. HEM.30070 states that if you have more than one sampling mode that you must annually compare results between the modes. Our Medical Director has set tolerance limits for this comparison. We do it monthly though it is only required annually. But, you are correct, you must run Coag QC every 8 hours! HEM.37300 Good Luck!