Aspects of the subject invention are drawn to methods, compositions, systems and kits for the assessment of oxidative stress in an individual from a blood sample. In certain embodiments, the expression level of VNN1 in blood cells from a subject (or patient) is assessed and used to determine the subject's oxidative stress state, where an increased/high expression level of VNN1 indicates that the subject is in a state of oxidative stress. Expression of VNN1, and optionally other genes, may be done by assessing nucleic acid and/or protein levels in the blood cells obtained from the subject.