CCM 185: Colloid osmotic pressure and osmolality

Question 1

What percentage of onoctic pressure is made up of albumin versus globulin?

Answer 1

albumin 60-70%
globulin 30-40%

Question 2

How do colloid osmometer oncotic pressure measurements differ between plasma and whole blood samples? How does the difference matter clinically?

Answer 2

whole blood will measure higher due to RBC contribution to colloid osmotic pressure - small difference - about 0.5 mm Hg - clinically not significant and both samples can be used

Question 3

What determines the osmolality of a sample?

Answer 3

number of particles

irrelevant: particle charge, size, shape, density