Multiplexed longitudinal measurement of protein biomarkers in DBS using an automated SISCAPA workflow

Background: The use of DBS for quantitative protein biomarker measurement has been hindered by issues associated with blood hematocrit variations and lack of detection sensitivity, particularly when multiple biomarkers are measured. Materials & methods: An automated, multiplexed SISCAPA analysis was used to normalize blood volume variations in DBS and quantify proteins of varying abundance in longitudinal specimens. Conclusion: The results showed that after normalizing the spot-to-spot hematocrit variations, peptide surrogates of protein biomarkers could be accurately quantitated in DBS. This allowed the establishment of baselines for a variety of biomarkers in multiple individuals and enabled detection of changes over time, thus offering an effective solution for longitudinal personal monitoring of biomarkers relevant in health and disease.