High throughput extended blood group typing for blood donors by MALDI-TOF MS

Every year, blood donation services lose donors due to sickness, age, or other personal factors. A new in-house assay of the DRK blood donation service West, developed for use on the MassARRAY® System simplifies the identification process for new donors by testing 26 different blood group antigens. Extended donor blood group typing is a cost-effective and time saving method. It can help to provide compatible blood for patients with rare antibodies or patients require very closely matched blood.

MALDI-TOF MS is used for high throughput donor blood group screening. The in-house assay is a PCR based method that allows the screening of 26 blood groups in a single batch. Antigens included are C/Cw, Co(a/b), Do(a/b), Fy(a/b), Fy/Fy0, Jk(a/b), Js(a/b) Kp(a/b), Lu(a/b), Lu(8/14), Kk, MN, Ss, Vel/Vel- and Yt(a/b). In a first step, donors suitable for screening had to be selected. Criteria included that a donor donated blood at least 4 times, should not be older than 50 years and should be blood group O or A. Almost every step in the process is partly automated, starting with the selection of donors, DNA isolation and data processing. Data is stored in the LIMS and available for our immunohematology laboratories at all times.

Since August 2022, almost 30.000 donors have been screened. Several donors with rare genotypes have been identified, allowing us to supply compatible blood to patients with rare antibodies. From 30.000 tested donors, 9 were Vel-, 33 Fy0, 37 KK, 5 Kp(a/a), 34 Lu(a/a), and 11 Lu(14/14). The fast and flexible process has also allowed us to test preselected donors for patients in an emergency situation, generating results in less than 24 hours. A different area of application is the genotyping of patients. Our system has been successfully used to genotype patients under therapy with Daratumumab. The medication can be obstructive for antibody screening and crossmatch and makes it necessary to determine the antigens Fy(a/b), Jk(a/b), Ss.

In-house molecular blood group typing by MALDI-TOF MS is a valuable tool for extended donor blood group genotyping. It is a high throughput technology that generates a turnover that can barely be matched by other molecular methods and certainly not from serological methods. Antisera becoming rarer and overpriced if generally available. The whole process is reliable, flexible and a big step towards automated data processing, saving time and reducing the risk of man-made mistakes.

No conflict of interest.