Interference of hemolysis on haptoglobin determined by kinetic immunonephelometry and comparison between phenotypes

The aim of the study was to check if a slight and non visible hemolysis to naked eye such as that induced by blood coagulation could interfere in the immunonephelometric measurement of haptoglobin, and if this interference was dependent on the protein phenotype. Results confirmed that blood coagulation induced a non visible hemolysis whose intensity markedly varied from one specimen to another. Under our conditions (kinetic measurement with a Beckman Coulter immunonephelometer), we observed with the sera a negative interference linked to the hemolysis induced by blood coagulation when compared to corresponding plasmas obtained with lithium heparinate (p < 0,005). It was checked also that this anticoagulant did not induce a positive interference. Hemolysis interference was not found phenotype dependent. These results lead us to recommend to perform haptoglobin measurements on heparinised plasmas.