Question

Which of the following is incorrect?

• A. Karl Landsteiner and A.S. Weiner discovered Rh antigen
• B. Rh factor is called D antigen
• C. Person having D antigen is called Rh−
• D. Person having D antigen is called Rh+

Hint:

D antigen present → Rh+ ; absent → Rh−

Answer 1

The Correct Option is C

This question tests the Rh blood group naming rule. Let's check each statement one at a time.

1. Karl Landsteiner and A.S. Wiener discovered Rh antigen: this is historically correct, they identified this antigen using rhesus monkey blood, which is where the name "Rh" comes from.
2. Rh factor is called D antigen: correct, the specific protein on the red cell surface behind the Rh system is named the D antigen.
3. Person having D antigen is called Rh negative: this is backward. If the D antigen is present on the red cells, the correct term is Rh positive, not Rh negative.
4. Person having D antigen is called Rh positive: correct, having the D antigen present is exactly what makes someone Rh positive.

Since presence of the D antigen defines Rh positive status, calling it Rh negative reverses the rule and is the false statement.

Let's summarize:

• D antigen present means Rh positive; D antigen absent means Rh negative.
• The third statement swaps this rule, so it is the incorrect one.

So the incorrect statement is option (3).