The Roche IgG Assay can be adapted to specific human IgG molecule(s) by a product-specific calibration. We provide a protocol where the Roche calibrator can be replaced by a sample of your individual IgG molecule with a known concentration, and the rest of the assay reagents are fully compatible, with no additional materials or hardware needed. Both the Cedex Bio Analyzers are capable of storing multiple custom calibration curves, allowing flexibility to expand the customization to obtain titers for multiple products.