In an antibody identification study with a 5-cell panel, which antigen could not be excluded?

In an antibody identification study, the primary goal is to identify specific antibodies present in a patient's serum by utilizing a panel of red blood cells with known antigen profiles. Each cell in the panel can have various antigens that interact specifically with antibodies in the patient's serum, leading to observable reactions such as agglutination.

To determine which antigen could not be excluded in this scenario, it’s important to understand how the panel works. If a specific antigen consistently causes a reaction with the patient’s serum across different cells, it suggests that the patient has an antibody against that antigen, indicating its involvement.

When the study indicates that one antigen (antigen 1 in this case) could not be excluded, it typically means that the testing did not rule out the presence of an antibody against that antigen. For instance, if antigen 1 shows a positive reaction with the patient's serum while others do not, there remains a possibility that the patient has antibodies directed against that antigen.

On the other hand, if other antigens can show consistently negative results, it allows for their exclusion, as the absence of agglutination indicates that no corresponding antibodies exist for those antigens in the serum. Hence, the determination that antigen 1 could not be excluded implies a