The ASTM F 2129-08 standard is widely utilized in the medical device industry as a means of assessing the corrosion performance of small implant devices. While a great deal of research has gone into development of the standard and the effects of various test parameters (e.g. scan rate, test solution, pH, temperature,etc.) on the measurement of breakdown potential (Eb), relatively few studies have taken the time to consider the protection potential (Ep) and its value as a measure of a materials ability to repassivate after pitting has initiated. As demonstrated in the round robin study presented in ASTM Research Report F04-1011 for ASTM F2129, a precision statement for Ep from both SS samples could not be defined due to the dearth of data obtained even after testing a large number of specimens of each material. The present study investigates the effect of varying parameters such as potentiodynamic scan rate, and the current density threshold for scan reversal, on the ability of the material to repassivate and the determination of Ep. These results are then compared with ‘Critical Potential for Pitting' measurements made in accordance with ASTM F 746 – another test designed to assess the ability of a material to repassivate after initiation of pitting and/or crevice corrosion – to determine how these results correlate.