NRDC and susceptibility to pneumonia measurement: The present results demonstrated that serum NRDC levels were also elevated in some patients with non-ACS cardiovascular diseases (CVD), such as acute pericarditis, Takotsubo syndrome (TTS), and congestive heart failure (CHF), and also in those with non-CVD, such as pneumonia, which may account for low specificity in the diagnosis of ACS.