Inflammatory responses evident in many diseases involve the generation of oxidants which can cause post translational modifications to proteins. Oxidative protein modifications such as carbonylation, halogenation, lipid peroxidation, nitrosylation, and thiol oxidation increase with increasing inflammatory response. Among these modifications, protein thiol oxidation appears to be particularly sensitive because of the high reactivity of thiols with oxidants. Albumin, the most abundant plasma protein contains a free thiol group which is susceptible to oxidation. We propose that albumin thiol oxidation (AlbOx) could be a useful biomarker to monitor changes in inflammatory activity. To measure AlbOX in humans and animal models, we developed a capillary electrophoresis (CE-AlbOx) method with high reproducibility (CV < 2%, n =60). The CE-AlbOx only requires a small volume of sample (2 µL of plasma or 8 µL blood), has total run time of 15 minutes, and can measure both reversible and irreversible oxidation which was validated through mass spectrometry. We tested the usefulness of CE-AlbOx as a biomarker by analysing samples from diseases with chronic inflammation (Duchenne muscular dystrophy-DMD), induced inflammation, and an anti-inflammatory drug. In dystrophy, albumin thiol oxidation increased by 34.1% ± 5 (n=6) in humans, 20.3% ± 6.0 in rats (n=7-8) and 18.3% ± 4.3 (n=8-9) in mice when compared to healthy controls. Treatment of dystrophic mice with an anti-inflammatory drug resulted in a 19.9% ± 3.2 (n=9) decrease in AlbOx. Inflammation induced by a pathogen and exercise in mice resulted in an increase of AlbOx by 16.9% ± 5.0 (n=7-8) and 25.3% ± 7.7 (n=8), respectively. Our results provide evidence that albumin thiol oxidation is a sensitive marker of oxidative stress and can be used to track progression of inflammation and treatment efficacy. To facilitate use by clinical researchers, we have adapted the method for use with dried blood cards (DBC). The DBC is very simple to use, with the collection of fingerprick blood taking less than a minute. Blood samples can be readily collected in the field or at home. These cards allow samples to be collected and dried at room temperature, and then sent to our laboratory via mail, so expensive cold chain logistics are not necessary.