Background/aim: To evaluate pregnancy-associated plasma protein A (PAPP-A), ischemia-modified albumin (IMA), procalcitonin, and troponin I levels as diagnostic markers of acute coronary syndrome in patients admitted to the emergency department. Materials and methods: The serum PAPP-A, IMA, procalcitonin, and troponin I levels were measured in 100 patients with acute coronary syndrome admitted to the emergency department and 100 healthy control subjects.