Stability of albumin redox state in long-term plasma storage: Implications for multicenter studies

Long-term storage of plasma samples is essential for studies requiring extended recruitment periods or for combining biobank samples across multiple centers. Here, we assessed the impact of four years of storage at −80 °C on the redox state of human serum albumin in plasma samples. We found statistically significant but minor shifts in human mercaptalbumin (HMA), human non-mercaptalbumin 1 (HNA1), and HNA2 fractions, with strong correlation between measurements performed at baseline and after four years. These findings support the reliability of HSA redox measurements in long-term stored samples and provide guidance for multicenter or longitudinal oxidative stress research.