Which test differentiates A1 from A2 phenotypes?

Which test differentiates A1 from A2 phenotypes?

• A. Anti-A1 lectin test differentiates A1 from A2
• B. Anti-B lectin differentiates A1 from A2
• C. Anti-A1 test detects B1
• D. Anti-A1 lectin test not used

Answer: (A)

Differentiating A1 from A2 relies on detecting the A1 antigen. Dolichos biflorus (anti-A1) lectin binds specifically to the A1 structure present on A1 red cells. When you test with this lectin, A1 cells will agglutinate because they carry the A1 antigen, whereas A2 cells usually lack the A1 antigen and do not agglutinate. This makes the anti-A1 lectin test the direct way to tell these two subtypes apart. The other options don’t fit because they either involve the wrong antigen (anti-B lectin tests for B antigen, not A subtypes) or make incorrect statements about what anti-A1 tests detect or whether the test is used.

Differentiating A1 from A2 relies on detecting the A1 antigen. Dolichos biflorus (anti-A1) lectin binds specifically to the A1 structure present on A1 red cells. When you test with this lectin, A1 cells will agglutinate because they carry the A1 antigen, whereas A2 cells usually lack the A1 antigen and do not agglutinate. This makes the anti-A1 lectin test the direct way to tell these two subtypes apart.

The other options don’t fit because they either involve the wrong antigen (anti-B lectin tests for B antigen, not A subtypes) or make incorrect statements about what anti-A1 tests detect or whether the test is used.