Glossary

Plasma

Plasma is the liquid fraction of blood, roughly fiftyfive percent of its volume, in which the cells are suspended. After centrifugation it forms the upper layer. It carries the platelets that PRP concentrates.

Figure

The plasma fraction

PLASMA about 55% of the column BUFFY COAT platelets and leukocytes. about 1%. Drawn to scale. This is the whole target. RED CELLS densest fraction. sediments first. CENTRIFUGAL FORCE

Figure. Roughly fifty five percent of the column, and the layer in which the platelets you want are suspended. Its density, about 1,025 kg per cubic metre, is the baseline every other fraction is separated against.

In practice

Plasma density is about 1,025 kg/m3, against roughly 1,040 to 1,060 for platelets and 1,090 to 1,100 for erythrocytes. That density difference is the entire basis of separation.

See also