Hemoglobin has a lifespan of 100-120 days in the red blood cell, which makes it an ideal candidate as a biomarker of chronic diseases. Glycated hemoglobin (HbA1c) is routinely used to measure the average blood glucose levels of diabetic people. However, HbA1c fails to distinguish secondary complications associated with diabetes such as retinopathy, nephropathy, nerve damage, and cardiovascular diseases. To a significant extent, these complications are caused by mitochondrial overproduction of superoxide. However, this chronic oxidative stress is not routinely measured in diabetic patients because a good biomarker is lacking. We propose that hemoglobin can also act as a new biomarker for chronic oxidative stress. Particularly, we have started investigating hemoglobin modifications by the lipid peroxidation products. This work is in collaboration with Canterbury Scientific Ltd, and has been funded by MBIE.