Aim HLA registries are a key resource to bone marrow donor programs, since they allow the selection of donors that are most likely to be compatible with patients in need for transplant. In order to be economically viable, this process usually employs analysis in three levels of resolution: low-resolution that only determines the allele group, medium-resolution that produces a list of possible allele codes and high-resolution level that uses DNA sequencing to determine the definitive allele code for the donor. However, all these methods are susceptible to error and could result in upload of faulty information to the genetic databases. If a certain donor presents rare allele codes (non common nor well documented – NCWD) this could be a good indicator that the analysis is probably wrong. In this work, we propose and develop an online tool that receives a CSV file (e.g. Fusion® report) containing medium and high-resolution genetic information of different donors and lists the number of common (C), well documented (WD) and NCWD alleles. Methods In the case of medium-resolution samples, which contains the locus, allele group and NMDP code, the system checks all possible alleles related to that NMDP code and locus, producing a list of C, WD and NCWD counters. A report in the form of a CSV file is also generated, so that the lab technician can double-check the analysis on donors that presented only NCWD alleles. The system also allows administrator users to update CWD and NCWD allele lists as well as the list of NMDP codes. Results The figure below shows an example of an analysis report produced by AlleleChecker. Conclusions An alpha version of the system is being evaluated by the HLA lab of Rio de Janeiro State Uniersity and can be a valuable tool to improve the quality of data stored in the Brazilian National Registry of Bone Marrow Donors (REDOME). Download high-res image (117KB) Download full-size image