What interferes with BCA assays?

Certain substances, especially reducing agents, can disrupt the BCA Assay even at low concentrations. For instance, concentrations as low as 5 mM of dithiothreitol (DTT) and 0.1 M of glycine can interfere with the assay results. Acidifiers, reducing sugars (e.g. glucose), and copper chelating agents (e.g. EDTA), lipids can also all interfere with the assay and impact the results. Hydrogen peroxide (H2O2) can also disrupt the BCA assay. Additionally, phospholipids can interfere with the assay by interacting with the BCA reagent, forming a chromophore that absorbs near 562 nm. This interaction can cause the assay to report higher than actual protein concentrations.