Human plasma protein levels alter the in vitro antifungal activity of caspofungin: An explanation to the effect in critically ill?

Reduced human plasma protein levels increase the antifungal activity of caspofungin in vitro, most likely by increasing the free concentration. Low plasma protein levels in critically ill patients with candidemia might explain a better response to caspofungin than expected from generally accepted target attainment and should be taken into consideration when assessing TDM based on total plasma concentrations.