There are a lot of methods to detect anti-granulocyte antibodies.
One of the best methods is the ELISA method MAIGA (Monoclonal Antibody Immobilization of Granulocyte Antigens) :
Bux J, Kober B, Kiefel V, Mueller-Eckhardt C: Analysis of granulocyte-reactive antibodies using an immunoassay based upon monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA). Transf Med 1993; 3:157-162.
International workshops revealed a combination of several methods as the best means for the detection of granulocyte antibodies.
Other tests are: the Granulocyte Agglutination Test (GAT), the Lymphocyte Immunofluorescence Test (LIFT) and the Granulocyte Immunofluorescence Test (GIFT).
Bux J: Challenges in the determination of clinically significant granulocyte antibodies and antigens. Transf Med Rev X No. 3 : 222-232, 1996.