The present invention provides a method for the measurement of the activity of
a plasminogen activator, such as urokinase plasminogen activator (uPA) or tissue
plasminogen activator (tPA) in a biological sample using an assay method characterized
by the inclusion of an elastase inhibitor in the assay mixture. The invention also
provides a diagnostic kit for the measurement of a plasminogen activator using
said method and a method of determining the effective therapeutic dose of a plasminogen
activator inhibitor using said method. Also provided is a method of preparing a
pharmaceutical composition.