Which test is used to detect IgG antibodies in a patient’s serum that react with donor red cells in vitro?

Which test is used to detect IgG antibodies in a patient’s serum that react with donor red cells in vitro?

• A. Direct antiglobulin test
• B. Antibody identification panel
• C. Crossmatch
• D. Indirect antiglobulin test

Answer: (D)

Detecting antibodies in a patient’s serum that can react with donor red cells in vitro is done with the indirect antiglobulin test. In this test, the patient’s serum is mixed with red cells (such as screening or donor cells) to allow any IgG antibodies present to bind to the cells. Then an anti-human globulin reagent is added to reveal those antibody bindings. If agglutination occurs, it shows that IgG antibodies in the serum are specific for antigens on donor red cells. This is the primary way we screen for clinically significant antibodies before transfusion. Direct antiglobulin testing, by contrast, looks for antibodies already bound to a patient’s own red cells in vivo, not free antibodies in serum. The antibody identification panel is used after a positive screen to pinpoint the exact antibody specificities. The crossmatch assesses overall compatibility between donor cells and recipient plasma but doesn’t specifically detect antibodies in the serum by itself; it often includes an indirect antiglobulin step, but its main purpose is to determine whether a particular donor unit is compatible.

Detecting antibodies in a patient’s serum that can react with donor red cells in vitro is done with the indirect antiglobulin test. In this test, the patient’s serum is mixed with red cells (such as screening or donor cells) to allow any IgG antibodies present to bind to the cells. Then an anti-human globulin reagent is added to reveal those antibody bindings. If agglutination occurs, it shows that IgG antibodies in the serum are specific for antigens on donor red cells. This is the primary way we screen for clinically significant antibodies before transfusion.

Direct antiglobulin testing, by contrast, looks for antibodies already bound to a patient’s own red cells in vivo, not free antibodies in serum. The antibody identification panel is used after a positive screen to pinpoint the exact antibody specificities. The crossmatch assesses overall compatibility between donor cells and recipient plasma but doesn’t specifically detect antibodies in the serum by itself; it often includes an indirect antiglobulin step, but its main purpose is to determine whether a particular donor unit is compatible.