Format Direct Quantification Identification Limit of Detection Use ELISA yes no 1-100 lot release testing process control Western Blotting semi yes 20-200 process characterisation (GPI-) Protein Chip yes yes 0.1-200 process control and characterisation

Table 2: Comparison of the (GPI-) protein chip, ELISA and Western blotting formats for assaying HCP during process analytics of protein drug production.