Hinghofer-Szalkay H, H Wurm
Der Einfluss von Hämolyse auf hochgenaue Dichtemessungen an Kapillarblutplasma mittels der Biegeschwingermethode
(Influence of hemolysis on capillary blood plasma density measurements using the mechanical oscillator technique)
J Clin Chem Clin Biochem. 1980; 18: 615-9

Sampling of capillary blood often yields slightly hemolytic plasma.

We investigated the influence of hemolysis on plasma density using the mechanical oscillator technique. Plasma density rose by approximately 0.1 milligram when the hemoglobin content increased by 0.5 milligram. These values correspond to 0.3% hemolysis and were not exceeded in more than 70% of the investigated capillary plasma samples.

In general, hemolysis must be taken into account if plasma density measurements are to be made with an accuracy better than 0.5 milligram, which corresponds to 2-3% of the plasma protein content.