Background: Eosinophilic cationic protein (ECP) has been widely investigated in the clinical practice as a potential biomarker for asthma. However, there are conflicting data concerning its validity in other respiratory disorders.
Methods: Serum ECP levels were retrospectively analyzed in 441 patients (227 males and 214 females) suffering from respiratory disease and visited for the first time, and in 33 healthy subjects (17 males and 16 females).
Results: The mean of ECP was significantly higher (p = .0001) in patients compared with healthy volunteers. No correlation was found between serum ECP value and peripheral eosinophil absolute number (p = .881; r = .007). The predictive model was significant only for asthma, with a sensitivity of 70% and a specificity of 74% (efficiency 73%).
Conclusions: This study demonstrates that serum ECP may be considered a marker for identifying only asthmatic patients with an efficiency of 73% and is not useful for the differentiation of other respiratory disorders.