Editing Coombs test (section)

====Blood transfusion preparation====
{{main|blood transfusion|cross-matching}}
The indirect Coombs test is used to screen for antibodies in the preparation of [[blood]] for [[blood transfusion]].  The donor's and recipient's blood must be [[ABO]] and Rh D compatible.  Donor blood for transfusion is also screened for infections in separate processes.{{cn|date=November 2021}}
* Antibody screening
A blood sample from the recipient and a blood sample from every unit of [[Blood donation|donor]] blood are screened for antibodies with the indirect Coombs test.  Each sample is incubated against a wide range of RBCs that together exhibit a full range of surface antigens (i.e. [[blood types]]).
* Cross matching
The indirect Coombs test is used to test a sample of the recipient's serum for antibodies against a sample of the [[blood donor|blood donor's]] RBCs.  This is sometimes called [[cross-matching]] blood.