haemagglutination

/HH EH1 M AH0 G L UW1 T IH0 N EY0 SH AH0 N/
noun
  1. 1

    The agglutination of red blood cells, especially as a test for the presence of antibodies

Source: https://en.wiktionary.org/wiki/haemagglutination, https://en.wiktionary.org/wiki/hemagglutination