Medical Laboratory Scientist (MLS) ASCP Practice Exam

The blood type phenotype Le(a+b-) refers to the presence of the Lea antigen and the absence of the Leb antigen. In the context of the secretor status, it is important to note that individuals who are Le(a+b-) typically possess the Le gene (Se allele) but do not express the Leb antigen.

The Le gene is responsible for the production of the Lewis antigens, and in individuals who are Le(a+b-), the genotype is usually Le le (where at least one allele is Le), and they exhibit the Lewis a antigen only, without the Lewis b antigen. The presence of Le(a+b-) indicates that the individual is secretor-negative concerning the Lewis blood group.

The option that corresponds correctly to this phenotype is typically Le sese, which identifies those individuals who do not secrete the Lewis antigens in their bodily fluids while maintaining the Lea status. This aligns with the characteristics of Le(a+b-) individuals.

In summary, Le(a+b-) indicates the presence of the Lewis A antigen (Lea) and the absence of the Lewis B antigen (Leb), alongside the secretor-negative phenotype, which is best captured by Le sese. This biological background provides a clearer understanding of how blood group phenotypes are classified in relation