Background: Patients with severe chronic kidney disease (CKD G4-G5) often have chronically elevated high-sensitivity cardiac troponin T (hs-cTnT) values above the 99th percentile of the upper reference limit. In these patients, optimal cutoff levels for diagnosing non-ST-elevation acute cor-onary syndrome (NSTE-ACS) requiring revascularization remain undefined. Methods: Of 11,912 patients undergoing coronary angiography from 2012 to 2017 for suspected NSTE-ACS, 325 (3%) had severe CKD. Of these, 290 with available serial hs-cTnT measurements were included and 300 matched patients with normal renal function were selected as a control cohort. Results: Diagnostic performance for patients with severe CKD was high at presentation and similar to that of the control population (AUC, 95% CI: 0.81, 0.75-0.87 versus 0.85, 0.80-0.89, p=0.68) and the ROC-derived cutoff value at presentation was 4 times higher compared to the conventional 99th percentile. Combining the ROC-derived cutoff levels for hs-cTnT at presentation and absolute 3-hour changes, sensitivity increased to 98%, PPV and NPV improved up to 93% and 86%, re-spectively. (4) Conclusions: In patients with severe CKD and suspected ACS the diagnostic accu-racy of hs-cTnT for the diagnosis of NSTE-ACS requiring revascularization is improved by using higher assay specific cutoff levels combined with early absolute changes.