The OPTN/UNOS Histocompatibility Committee (the Committee) created this guidance document in order to provide additional information or clarification for the OPTN/UNOS bylaws and policies. This guidance document is designed to assist members with interpreting the bylaws and policies governing histocompatibility laboratories and histocompatibility testing of donors and candidates.

This guidance document is intended only to provide guidance for labs on certain aspects of histocompatibility testing and written agreements. The guidance given for testing is not intended to overrule the clinical needs of a patient. Additionally, the scope and content of written agreements should reflect collaboration between laboratories and transplant programs, taking into consideration their needs and laboratory best practices.

This project was initiated during the histocompatibility bylaws and policies rewrite in 2014. During that time the Committee decided that several sections of bylaws and policies were better suited as a guidance document, as they provided recommendations for histocompatibility laboratory performance, rather than requirements. In total, 28 sections of policy fell into this category. The Committee reviewed those sections, and decided to omit certain sections that referenced out of date components of histocompatibility testing, or because they related to testing standards better governed by lab accrediting agencies like the American Society for Histocompatibility and Immunogenetics (ASHI) and the College of American Pathologists (CAP).

The remainder of the document focuses on the written agreements between histocompatibility labs and transplant programs, cross matching, blood typing, and preservation and storage of excess specimens. These topics were chosen for inclusion in this guidance document based on two factors. First, they are
what remains of the original 28 sections of policy flagged for inclusion that are not out of date or reflective of testing standards governed by the accrediting agencies. Second, they are representative of questions received by UNOS from members of the transplant community.