Introduction:

The KAS allocates A2 and A2B donor kidneys to blood type B candidates. Research is limited and variability exists among centers regarding the significance, relevance, and appropriate eligiblity criteria of pre-transplant anti-A titers. In order to develop an efficient and cost effective management process, research is needed to determine if pre-transplant titers vary over time and the needed frequency of measurement.

Methods:

Anti-A titers were performed quarterly over a 1 yr period for all type B candidates listed for kidney transplant with candidates having from 1 to 3 titer measurements (M1-M3). Eligibility required titer results of both IgG < 1:8 and IgM/IgG < 1:64. Candidates were classified as either eligible or ineligible based on these criteria. Agreement between M1 and M2 was assessed using nonparametric tests. Logistic regression tested the association of stability between M1 and M2 and the likelihood of being ineligible at M3.

Results:

Cohort included 114 candidates (52+11 yrs; 66% male; 61% Black) with IgG and IgM/IgG titers at M1 and M2. 81 candidates had titers at 3 measurements points. Table 1. shows titer based eligibility status at each point. Candidates eligible at M1 were more likely to be eligible at M2 (p<0.001). Variability in eligibility status between M1 to M2: 25% remained eligible, 56% remained ineligible, 26% changed ineligible to eligible or eligible to ineligible. Candidates who are stable eligible or stable ineligible at M1 and M2 are more likely to maintain that same status at M3 (p<.001) (Table 2).

Conclusions:

26% of titers varied over time suggesting these candidates need continued titer monitoring. Candidates with stable eligibility status after two measurement points are more likely to maintain that same status at subsequent measurements limiting the need for repeated measurements to only candidates who display variability in eligibility. Thus eliminating unnecessary testing and cost.

CITATION INFORMATION: Moore D, Feurer I, Forbes R, DeMers A, Shaffer D. Pre-Transplant Anti-A Titers in Waitlisted A2 to B Kidney Transplant Candidates. Am J Transplant. 2016;16 (suppl 3).

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