From Susan Lemire, Elliot Hospital, New Hampshire
Hi George, I am validating the new Sysmex XN analyzer and they do not support a citrated platelet count for clumped platelets. In order to continue our current process, I am in the midst of doing a correlation between EDTA platelet counts vs. citrated counts. I have found there to be a 20–25% difference between the two values, the citrated platelet count being lower even after the 1.1 multiplication factor. Does this seem accurate? I am considering still offering a PLT and wondering if I need to attach a disclaimer to any reported citrated platelet. How would you proceed?
Hello, Susan, and thank you for an interesting question. Though I’ve always used the citrated specimen platelet count for instances of platelet clumping or satelliting, I can’t recall ever performing a correlation between EDTA and citrated specimens for patients without clumping or satellitism. Your approach of appending a disclaimer seems correct to me, and meanwhile, I’d like to learn what others have seen when attempting correclations.
French colleagues showed
French colleagues showed similar results, underestimation of PLT count in citrated specimen even after 10% correction vs EDTA samples. One can get more details from full text (unfortunately French only) or just check data from illustrations/graphs, attached to the text:
Védy S et al. Automatic platelets numbering with citrate as anticoagulant: is the result valid?. [Article in French] Ann Biol Clin (Paris). 2011 ;69:453-8.