Eras of the APD showing problems identified, solutions, and the impact of modifications on the reasons for failure, 1-way success rate, and transplants/year. *Upon reviewing laboratory data, 26 positive crossmatches were found in 2007 that accounted for 31% of the 83 failed offers. However, because all failure data was not systematically collected in 2007, these 26 XM failures were not incorporated into the overall failure analysis.