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Blood Agglutination Test

Yezi Cho

American Community School of Abu Dhabi

Blood types were determined by an agglutination test using anti-A and anti-B serums.

Using alcohol swabs and an automatic lancet, blood samples were collected.

A drop of anti-A serum and anti-B serum were each added to the blood samples.

  1. Agglutination occurring with anti-A serum - blood group A

  2. Agglutination occurring with anti-B serum - blood group B

  3. Agglutination occurring with anti-A and anti-B serum - blood group AB

  4. Agglutination occurring with neither serum - blood group O

People with blood type A have the A antigen on the surface of their red blood cells; they do not have anti-A antibodies. If a donor's blood of type B or AB is transfused, the anti-B antibodies of the recipient would cause agglutination.

If a blood sample is agglutinated by the anti-A serum/antibody but does not react with the anti-B serum/antibody, the A antigen is present while the B antigen is absent, meaning the blood is group A.

Blood type AB produces both the A antigen and B antigen, so the blood sample would agglutinate with both serums.

Blood type O does not produce any antigens, so the blood sample would not agglutinate with any serum.

Below are blood samples and results taken from three individuals.

Blood type O

Neither serums caused agglutination.

Blood type B

Anti-B serum caused agglutination while anti-A serum did not.

Blood type A

Anti-A serum caused agglutination while anti-B serum did not.

Blood type AB was not observed in any trials.

(Source: Wikimedia Commons)

Additionally, the anti-D serum can be used to determine whether the blood is positive or negative. Agglutination indicates a positive blood type, while having no reaction indicates a negative blood type.

All samples were disposed according to medical waste disposal guidelines.


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