We examined whether changes in posttransplant highest intensity donor specific anti-HLA antibody specificity (DSAmax) measured by single antigen bead via Luminex (One Lambda, Inc.) were associated with antibody-mediated rejection (AMR). We conducted a retrospective analysis examining risk factors for AMR in 116 consecutive patients who underwent desensitization between 1/1/2009 and 9/1/2010. All patients had a negative flow cytometry crossmatch. The mean patient age at transplant was 46.4 +/- 4 years. The mean peak PRA (panel reactive antibody) and DSAmax at transplant were 40 +/- 6% and 894 +/- 150 mean fluorescent intensity (MFI), respectively. The mean time to rejection was 1.5 +/- 0.4 months. Cox regression analyses demonstrated that an increase in DSAmax by one week after transplant was significantly associated with AMR (pure or mixed). A rise in DSAmax greater than 500 MFI at 1 week was associated with a 2.6 times greater risk of rejection (HR 2.6, 95% CI 1.1 - 6.3, p = 0.02). We conclude that a rise in DSAmax at one week is an independent risk factor forAMR and that posttransplant DSA monitoring strategies may reduce the risk of AMR in sensitized patients.