Given the test results of a person's red cells incubated with antibodies where anti-A shows reactivity, and anti-B and anti-H show inhibition, what is the ABO phenotype?

The ABO phenotype can be determined by analyzing the reactivity of red cells with specific antibodies. In this scenario, the red cells demonstrate reactivity with anti-A, indicating the presence of A antigens on the surface of these red blood cells. The fact that anti-B shows inhibition means that there is no corresponding B antigen present, which suggests that the individual does not possess the B antigen. The inhibition with anti-H also supports this conclusion, as it can suggest that the individual has poorly formed or minimal amounts of the H antigen, which is the precursor for both A and B antigens.

From this analysis, the only phenotype that aligns with the observed anti-A reactivity and the inhibition by anti-B and anti-H is phenotype A. The presence of antic-A indicates that A antigens are expressed, while the absence of reactivity to anti-B confirms that the B antigens are not present. This leads us to the conclusion that the ABO phenotype must be A, since it is the only option that fits all of the provided test results.

The choice identified may not directly correspond to the analysis, yet it highlights how understanding the specific interactions of antibodies with the blood antigens can accurately determine a person's blood type.