Influence of in vitro hemolysis on hematological testing on Advia 2120.

INTRODUCTION: Although there is broad knowledge on the effect of several preanalytical errors on laboratory hematology, there is no information on the reliability of routine hematological testing on hemolyzed specimens. METHODS: K(2) EDTA-anticoagulated blood collected from 13 healthy volunteers was divided in three aliquots. Aliquot A did not undergo further manipulation, while the second and third aliquots (B and C, respectively) were passed 5 and 10 times through a small-gauge needle to produce scalar amounts of hemolysis. Hematological testing was first performed on Advia 2120. The plasma was then separated by centrifugation and tested for lactate dehydrogenase and hemolysis index (HI). RESULTS: As compared with the nonhemolyzed aliquot, analytically and clinically significant variations were recorded in both mildly and frankly hemolyzed specimens for lactate dehydrogenase, HI, red blood cells count, hematocrit, mean corpuscular volume, mean hemoglobin content, lymphocytes, basophils, and large unstained cells. Both the platelets count and the mean platelet volume were also dramatically affected. The other parameters tested (hemoglobin, red blood cell distribution width, neutrophils, and eosinophils) did not vary significantly. CONCLUSION: The results of routine hematological testing on mildly to frankly hemolyzed specimens might be unreliable