Evaluation of the Clinical Performances of a Point of Care Analyzer Enabling Pre-transfusion ABOD Group Ultimate Verification at the Patient Bedside

ABO-incompatible red blood cell transfusions still represent an important hazard in transfusion medicine. Therefore, some countries have introduced a systematic bedside ABO agglutination test checking that the right blood is given to the right patient. However, this strategy is entirely manual, requires an extremely time-consuming learning program and relies on a subjective interpretation of agglutination on ABO test cards (for example Biorad, Diagast).

The ULB spinoff Antigon developed a prototype device on the basis of a technology developed in the Translational research laboratory of CHU-Brugmann, ULB. This device is specifically dedicated to perform a "near patient" control of the blood group of the patient and of the blood bag just before transfusion, and to control that the right blood bag is given to the right patient by cross-checking their identifications. The principle of the assay relies on an agglutination and filtration in a disk including anti A,B and D antibodies.

Results of a preliminary study using a first Proof of Concept Prototype demonstrated the feasibility of ABO determination with a simple device, eliminating manipulation and subjective interpretation responsible for transfusion errors.The investigators then developed an end-user friendly, portable device using disposable fluidic disks and including everything needed to perform an agglutination test to determine the ABO group + RHD status of a patient and a blood bag, or alternatively of two patients.The system is designed to be used near the patient just before the beginning of transfusion.

The goal of this study is to validate the analytical performances of this device (phase A) and to validate the clinical performances of this device (phase B).

Phase A will be conducted in the laboratory and will allow the determination of the cut off values for the quantitative optical measures. These cut-off values will define the presence or absence of antigens A, B or D. Blood groups will be determined using the prototype and compared to the blood group determined in the blood transfusion laboratory with an automate using gel filtration technology. The validation will be performed both on blood bag samples and on random EDTA blood samples collected from consecutive unselected patients of our institution for whom a blood group had been requested (no additional sampling procedure nor additional blood volume will be required). The performances of the defined cut-off values will be tested in a second step on additional blood pathological samples selected from the routine samples received at the laboratory. They will cover a large range of hematological and immunological anomalies susceptible to interfere with or impair test performance and results. Finally, tests will be run on residual blood samples of neonates.

Phase B will be conducted to investigate the performances of the device in real conditions for the ultimate control of the ABO compatibility by comparing the patient and blood bag ABO groups. It will be conducted for its most part inside the laboratory and for another part in clinical units where the test will be performed by the nurses, with the assistance of the technologist involved in the validation of the device. For the part of the study conducted inside the lab, blood bags routinely attributed to patients will be selected the be tested on the device in parallel with the blood from the correct patient or from a 'wrong' (with other blood group) patient, in order to simulate situations of transfusion errors and evaluate the performances of the device to identify and block these errors. If the results are satisfying, the device will be tested in real life at the bedside in real conditions of transfusion. For this part of validation the results provided by the device (expressed as Compatible/not compatible/undetermined) will be compared with the results obtained with the manual point of care compatibility control (according to local procedure), and with the known groups of the patient and the blood bag stored in the patient blood bank file.

The number of ABO tests both on patients and on blood bag from donors has been determined in accordance with the recommendations from European Commission for Technical Specifications for In vitro diagnostic medical devices. ABOD assay performances have to be evaluated on at least 3000 samples.