[The colloid osmotic pressure of blood. Physiology, measuring technique and pre-analytic factors of influence].

Since the fundamental work of Starling the central of colloid osmotic pressure for maintaining volume homoeostasis and for transcapillary fluid exchange has been well known. To treat an intravasal volume deficit colloidal plasma substitution solutions are able to secure a sufficient colloid osmotic pressure. The last one can be measured by oncometry. Therefore an individual therapy is possible. This review describes the physiologic function, measurement techniques and important influencing parameters and disturbing factors which may be taken into consideration when colloid osmotic pressure is determined.