Analysis of serum total and free PSA using immunoaffinity depletion coupled to SRM: correlation with clinical immunoassay tests

► Measurement of serum total and free PSA without specific PSA antibodies. ► Low ng/mL LOQ for both total and free PSA measurement. ► Good correlation with immunoassay tests (R2 0.90-0.99). ► Biomarkers with similar complexation properties can be measured simultaneously.