Procalcitonin-based diagnosis of infections or inflammatory diseases of the respiratory tract in a patient with heart failure

An in vitro method for diagnosis of an infection or inflammatory disease of the respiratory tract, in a patient having cardiac insufficiency, comprising:

• determining the level of the biomarker procalcitonin or fragments thereof, in a sample obtained from said patient, and employing a threshold value which is used to indicate when said patient has an infection or inflammatory disease of the respiratory tract with associated cardiac insufficiency, said threshold value being a level of procalcitonin or fragments thereof that is between 0.03 ng/mL and 0.25 ng/mL.