An evaluation of four methods for the measurement of elastase activity.

The precision of four different methods for the measurement of low levels of porcine pancreatic elastase was assessed using a synthetic substrate and by three other methods using the natural substrate elastin. The most precise method used the synthetic substrate Succ(Ala)3NA (within-batch coefficient of variation = 1.9%, between-batch coefficient of variation = 2.5%). Fluorescein-labelled elastin was the most precise of those methods using elastin as substrate (within-batch coefficient of variation = 5.1%, between-batch coefficient of variation = 5.5%).