Current fuel cell diagnostic techniques are time-consuming for end-of-line testing in mass production, and improvements can significantly reduce costs. This thesis aims to design a rapid end-of-line fuel cell stack test for catalyst layer characterization using the galvanostatic charge method (GCM). GCM estimates electrochemically active surface area (ECSA) and hydrogen crossover with multiple voltage measurements at steady currents and a model to extract empirical parameters. In the proposed test, hydrogen crossover is measured separately, enabling ECSA estimation with a single galvanostatic measurement, reducing test time, and eliminating extrapolation errors. ECSA, hydrogen crossover, double layer capacitance, and cell ohmic resistance are measured on single cells before and after break-in under varying conditions. Results are validated by cyclic voltammetry and linear sweep voltammetry. The method successfully identified a defected cell with a 26.58% missing catalyst area in a 4-cell stack. Incomplete desorption and faster charging distinguished defected cell from conforming cells.