Final answer:
In the provided blood typing case indicating reaction to Anti-A and no reaction to Anti-B, the patient's blood type is most likely A. However, polyagglutination and technical error possibilities suggest further investigation is required to determine the correct blood type.
Step-by-step explanation:
The phenomenon of polyagglutination is observed in blood typing when a patient's red blood cells agglutinate with more than one type of antiserum. In the scenario presented where Anti-A yields no reaction (0), Anti-B yields a reaction (+mf), and blood cells react with A cells (4+) and not with B cells (0), it suggests the presence of antigen A and the absence of antigen B on the patient's red blood cells.
Considering the typical response in ABO blood group determination, a patient whose blood cells agglutinate with anti-A and do not agglutinate with anti-B has blood type A. However, the additional 'mf' (multifocal) notation with the Anti-B result indicates the possibility of an abnormal condition or technical error that would warrant further investigation.
In summary, a patient's blood type is primarily determined by the presence or absence of antigens. Individuals with blood type A have antigen A on their red blood cells and produce anti-B antibodies, which would result in no agglutination with Anti-B serum. Polyagglutination, whereby red blood cells agglutinate with multiple antisera, would be inconsistent with standard typing results and suggests further analysis is required.