The present invention relates to a method of differentiating between a singular and a multiple lung embolism in a subject suspected to suffer from acute lung embolism comprising determining the amount of NT-proBNP in a sample of a subject suspected to suffer from acute lung embolism and comparing the amount to a reference amount. Further, the present invention also relates to a method of differentiating between acute and chronic lung embolism in a subject comprising determining the amount of NT-proANP at a first and a second time point and comparing the determined amounts with each other. The present invention also encompasses devices and kits for carrying out the aforementioned methods.