This question arrived January 8 from Twyla Bader MT (ASCP), Heme/Coag Supervisor at St. Joseph Hospital, Bellingham WA:
We use Diagnostica Stago’s STA Compact analyzers and their LIA D-dimer reagent. Their package insert states there is no interference by hemolysis up to 5.0 g/L HGB. We did find a discrepancy between a hemolyzed sample and a nonhemolyzed recollection from the same patient with little time elapsed. We suspect it was due to a traumatic collection (indicated by hemolysis) that activated the coagulation cascade and resulted in D-dimer produced during the collection process in vitro. What do you think, is it possible to have a considerable amount of D-dimer result from the collection process alone?
Twyla, sorry to be slow in answering this one, I’ve spent a couple of days searching for papers that directly relate specimen hemolysis to the D-dimer and couldn’t find any that are specific. Maybe one of our other participants has an answer. These are the kinds of issues Dave McGlasson and Kim Kinney like to tackle, and maybe Bob Allen at Stago has done some internal tests.
Meanwhile, although I’ve found no direct research evidence, visible hemolysis is almost always evidence for specimen mismanagement, and rough handling is likely to activate platelets and coagulation in vitro, leading to D-dimer production, so your conclusion is probably correct. CLSI Standard H21-A4 states, “Samples that have visible hemolysis should not be used because of possible clotting factor activation and end point measurement interference.”
Back when we were performing semiquantitative FDP assays on serum (and many still do), the specimen collection tube contained thrombin, which generated an instantaneous clot. This was to prevent in vitro generation of FDPs. To generalize from this experience, rough handling of a plasma specimen may have the same effect. Geo.
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