Plasma exudation. Correlation between Evans blue dye and radiolabeled albumin in guinea pig airways in vivo.

We quantified the tissue exudation and luminal transudation of two plasma markers, Evans blue (EB) dye and [125I]-human serum albumin (HSA), into the airways of the anesthetized guinea pig in response to platelet activating factor (PAF). There was a highly significant correlation between the tissue content of EB and [125I]-HSA in all airways studied. Significant correlation for transudation of the two markers was limited to high rates of plasma leakage. [125I]-HSA was the more sensitive marker for the association between exudation and transudation and the effect of PAF on transudation. EB was the better marker for assessing the relationship between the dose of PAF and plasma exudation.