Influence of mechanical hemolysis of blood on two D-dimer immunoassays.

Although there is broad information about the influence of spurious hemolysis on several laboratory tests, less is known on the bias produced on D-dimer testing. Four different pools were obtained from primary blood tubes, and each of them was divided into four aliquots. The first nonhemolyzed was centrifuged, the plasma was separated and then tested for hemolysis index and D-dimer. The second (hemolyzed aliquot A), third (hemolyzed aliquot B) and fourth (hemolyzed aliquot C) aliquots were mechanically hemolyzed by aspirating whole blood one, two and three times through a fine needle. The plasma was then separated and tested for hemolysis index and D-dimer. D-dimer was quantified by HemosIL AcuStar D-dimer and HemosIL D-dimer HS for ACL TOP. Undetectable hemolysis was present in aliquot nonhemolyzed (