Purpose:
To inform To inform all physicians and staff that the Department of Pathology and Laboratory Medicine HLA Laboratory will eliminate thymoglobulin depletion in serum samples for testing anti-HLA antibodies.
Rationale:
Currently, detection of anti-HLA antibodies utilizes analytically-sensitive multiplexed immunoassays (Luminex). Due to concern that the presence of thymoglobulin in peripheral blood samples could interfere with immunoassays for detection of anti-HLA antibodies, it has been standard practice at the UC Irvine HLA Laboratory to pre-treat serum from patients receiving anti-thymocyte globulin for removal of thymoglobulin. However, current UCI HLA Laboratory practice of routine serum pre-treatment with DTT also effectively reduces non-specific antibody binding, suggesting that these practices may be redundant.
To evaluate this, we performed parallel testing on 6 serum samples from patients having recently receiving thymoglobulin treatment using current UCI HLA Laboratory method of thymoglobulin-depletion and DTT or the current UCI HLA Laboratory method of DTT treatment alone. The serum pre-treatment methods concordantly identified 101/125 (80.8%) of anti-HLA antibodies. Discrepant results were primarily (22/24) for antibodies that were detected only in the absence of thymoglobulin removal. Evaluation of discrepant results suggests that discrepancies were likely attributable to standard assay variability. The high degree of correlation between methods and the fact that the majority of uniquely identified antibodies were detected in DTT treated serum suggests that anti-thymoglobulin pre-treatment is not providing additional benefit in antibody detection. Discontinuation of anti-thymoglobulin serum pre-treatment will improve clinical workflow, reduce reagent and QC expenditure, and is unlikely to negatively affect patient care. Successful performance of these validation tests ensures that the test methodology for detection of anti-HLA antibodies is accurate and provides the highest quality information for clinical decision making.
Ordering and reporting will not change- thymoglobulin depletion serum treatment is not ordered by physicians but dictated by laboratory SOP.
Please see UCI Laboratory Directory (http://www.pathology.uci.edu/services/) for:
1. Specimen Requirements
2. Rejection Criteria
3. Methodology
Implementation Date: March 1, 2018
Gerald P. Morris, MD, PhD
Director, HLA Laboratory
Edwin S. Monuki, MD, PhD
Chair, Department of Pathology & Laboratory Medicine
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