Analysis of Beckman Coulter ACCESS AccuTnI+3 assays will take place on UniCel DxI 800 immunoassay system in the Singapore General Hospital (SGH) Pathology. Analysis of ARCHITECT hsTnI assay will take place on Abbott ARCHITECT i2000 analyzer in the National Heart Centre Singapore (NHCS) Laboratory. Calibration, Calibration verification, cross-over validation, and daily Quality Control for the hsTnI assay will be performed by medical technologists in conjunction with normal laboratory operations.