In Redrum (I think that's the title) Keppler showed Catherine the bag of 'donated' blood from their fake victim. Later Nick tests the blood and finds high levels of EDTA. 'Cuse me?? The blood bag clearly shows CPDA-1 (citrate- phosphate- Dextrose- Adenine) as the anticoagulant. So why did Nick find high levels of EDTA (ethylenediaminetetraacetic acid)????? They goofed up on that one!