agglutination

https://doi.org/10.1351/goldbook.A00183
An immunochemical reaction leading to the aggregation of particulate matter such as bacteria, erythrocytes or other cells, or synthetic particles such as plastic beads coated with antigens or antibodies.
Source:
PAC, 1992, 64, 143. 'Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)' on page 145 (https://doi.org/10.1351/pac199264010143)