Photometric evaluation of the solid-phase antiglobulin test using length measurement of the absorption curve

The very sensitive solid-phase antiglobulin test is used widely in blood group serology. However, a disadvantage of the test is the sedimentation variability of indicator cells during centrifugation, which causes errors in the photometric evaluation.To solve this problem a technique was developed which depends on the 'length measurement of the absorption curve' of the sedimented indicator cells.9,075 sera were tested for the presence of alloantibodies on the basis of the visual type of measurement and the newly developed technique. The agreement between the two evaluation systems was 99.94%. No false-negative results were observed.The new method allows the complete automation of the solid-phase antiglobulin test, enabling the analysis and evaluation of the solid-phase microtiter plate assay to be more discriminating and safe.