Simple image analysis for reliability control of column agglutination test in pretransfusion testing

A novel meniscus-based analysis provides a rapid method to identify analytical errors related to unrecognised pipetting errors.

The indirect antihuman globulin test (IAT) is part of pretransfusion testing, enabling detection of erythrocyte alloantibodies. Failure to detect such antibodies may result in transfusion complications. In column agglutination technique (CAT)-based IAT, correct separation of the different liquids by an air gap during incubation is essential. Penetration of this air gap due to pipetting errors can cause neutralisation of AHG, resulting in false-negative or weak test results.

We investigated the fluid dynamics of CAT-based IAT and developed a simple image-based quality control approach to detect air gap penetration. Using routinely generated analyser images, the meniscus contact angle was quantified with the software ImageJ in 132 simulated crossmatch tests.

Receiver operating characteristic analysis demonstrated high discriminatory performance (AUC 0.935). Additional experiments using bovine serum albumin solutions confirmed that increased protein concentration significantly reduces meniscus contact angle, supporting the proposed mechanism of error prediction.

While further validation across platforms and laboratories is required, this approach has the potential to enhance test reliability, support troubleshooting, and improve patient safety in routine IAT CAT workflows.