Moser M, H Hinghofer-Szalkay, T Kenner, H Holzer
The colloid osmotic pressure of blood plasma is a function of the total concentration of plasma proteins; this applies to plasma mass density as well. Thus, plasma colloid osmotic pressure can be determined from measurement of plasma density.
Minor variations are caused by variations of the albumin-globulin ratio and, much less frequently, by increased concentration of low molecular substances in the plasma. The direct measurement of the colloid osmotic pressure is a time consuming and complex procedure.
The determination of the plasma density using the mechanical oscillator technique is a simple and fast procedure. We offer an equation to compute colloid osmotic pressure from plasma density. The plasma volume needed for the measurement is 0.2 ml, the measuring time amounts to a few seconds.