Abstract: Methods for the early sensing of tissue ischemia and/or infarctions within organs using the spectroscopic features of serum luminescence include (i) isolating serum from a blood sample, (ii) directing an excitation light at the serum, (iii) receiving an endogenous serum chromophore emission light from the excited serum, and (iv) determining a presence of an ischemic condition based on the intensity of the endogenous serum chromophore emission light. Methods of detecting organ dysfunction can include transmitting excitation light to luminal contents of a mammalian blood vessel comprising trace amounts of exogenous chromophores administered to the subject mammal via the circulatory system. Transdermal luminescence measurements from the trace amounts of exogenous chromophores can then be used to determine organ dysfunction.