What is the name of the blood typing system that does not test for the Rh factor?

The Lewis system is a blood typing system that specifically focuses on antigens found on the surface of red blood cells and does not include testing for the Rh factor. This system is distinct from the ABO blood group system, which categorizes blood based on the presence or absence of A and B antigens, as well as the Rh factor, which determines whether the blood type is positive or negative.

Understanding the Lewis system is essential for blood transfusions and organ transplants, as it provides information about certain antigens that can influence compatibility. The other groups, such as the ABO system and the major blood group system, involve the assessment of the Rh factor. The minor blood group systems encompass various additional antigens but also do not exclusively exclude the assessment of the Rh factor like the Lewis system does.

By focusing exclusively on the antigens unique to the Lewis system, it becomes clear why this is the correct answer to the question regarding a system that does not test for the Rh factor.