#1 May the Plex Be with You — Serum or Plasma: What Sample Do I Choose for My Multiplex Biomarker Assays?

Sample measurements can differ for serum and plasma. Why?

• Serum is qualitatively different from plasma because of how the removal of fibrinogen and other proteins that form fibrin clots affects coagulation
• Protein concentration of serum is ~3–4% less than that of plasma

Choose sample matrix measurements that fall within the linear portion of the standard curve. This will allow for better precision and accuracy.