Here is a question from Fiona McCall at Siemens:
Do laboratories investigate their normal PTT reference range routinely? I have concerns that laboratories try to determine the factor VIII & factor IX sensitivity of their PTT reagent without really knowing what is an abnormal PTT for their current PTT reagent lot number. Can anyone share with me the method they use for measuring the factor sensitivity of their PTT reagent.Your opinion on this would be greatly appreciated.
regards, Fiona McCall
Hello, Fiona. I believe most coagulation laboratory directors require a new reference range and therapeutic range be generated with each reagent lot number change, however, I suspect few of us routinely check for factor VIII and IX sensitivity. For me and for our participants, I’d also like to understand the relationship between the reference range and reagent sensitivity. Geo.