Differences associated with pre-analytic factors averaged 6.1 % 4.6 % ; the three largest statistically significant changes ( 95 % confidence interval ) were : PCT , +14.2 % ( +2.1 % to +26.4 % , p = 0.02 ) with liver insufficiency ; ProADM , +13.2 % ( +10.2 % to +16.1 % , p < 0.01 ) with age above median ; CRP , -12.8 % ( -25.4 % to -0.2 % , p = 0.05 ) with steroid pretreatment .