Quantitation of oxidized and reduced albumin in mammals. An intriguing analytical question

Oxidized albumin is considered a short-term biomarker of oxidative stress and its measurement in blood contributes to evaluate the impact of diseases, drugs, dialytic treatments, physical activity, environmental contaminants etc. on the red-ox balance of humans as well as of other mammalians. Nevertheless, the most common methods for quantifying the oxidized and reduced albumins are costly and time-consuming. Furthermore, there is a dearth of information regarding the proper ways to store human serum or plasma samples in order to prevent inaccurate quantification of these various albumin forms. This paper explores these aspects and proposes a few spectrophotometric assay procedures which make the quantitation of oxidized and reduced albumin very fast, precise and un-expensive in various mammals. [Display omitted] •Oxidized serum albumin is a short-term biomarker of systemic oxidative stress.•DTNB, DTNB/Cystamine and DTNP assays are accurate, fast and unexpensive procedures to quantify reduced or oxidized serum albumin.•Cys34 in serum albumin has particular kinetic properties toward DTNB, DTNP and Cystamine.•Stability of oxidized serum albumin is influenced by pH and temperature.•Improvements of oxidized serum albumin stability can be obtained using a buffer solution and a centrifugation step.