Background: Ischemia-modified albumin (IMA; Ischemia Technologies, Inc), a new marker of myocardial ischemia, is known to elevate during ischemia induced by percutaneous coronary intervention (PCI). However, it is not known whether IMA elevates also during transient coronary vasospasm in variant angina. Subjects and Methods: We compared IMA levels in patients undergoing intracoronary ergonovine provocation tests(N=16), elective PCI (N=15) and subjects whose coronary angiograms were normal on diagnostic angiography (N=8). Positive provocation test was defined by at least two of the following components including typical ischemic chest pain, ST segment elevation, or occluded coronary artery with TIMI grade flow of less than 2. Blood samples were taken from the arterial sheath before procedure, just after procedural completion or balloon inflation, and 6 hours after procedure. IMA was measured by the albumin cobalt binding test. Results: In patients whose provocation tests were positive, the IMA level elevated significantly from baseline (N=9, 103.4짹9.7 vs 170.1짹70.3U/ml, p=0.008). The level did not elevate significantly in patients with negative provocation tests(N=7, 107.6짹7.7 vs 114.0짹5.7 U/ml, p=NS). The IMA level elevated significantly after PCI (N=15, 119.9짹21.3 vs 176.3짹56.4U/ml, p=0.001) also, which was coequal with the elevation in patients with positive provocation tests. In the normal group, the level did not change significantly after coronary angiography. It returned to baseline level at 6 hours after procedure in all patients. Conclusions: IMA is not only a sensitive marker of myocardial ischemia induced by PCI but also can be used as a reliable biological serum marker for transient myocardial ischemia induced by coronary vasospasm in variant angina patients.