Final answer:
In emergency situations, if the patient's blood type cannot be established immediately, a universal donor with type O blood can be transfused. Type O blood does not display A or B antigens, so there will not be an antibody reaction in the patient's blood plasma. However, there may be some adverse effects due to the presence of antibodies.
Step-by-step explanation:
In emergency situations, when the patient's blood type cannot be established immediately, blood from a universal donor with type O blood can be transfused. Type O blood does not display A or B antigens on the erythrocytes, which means that any circulating anti-A or anti-B antibodies in the patient's blood plasma will not encounter any matching antigens on the donated blood and will therefore not cause a reaction.
However, it's important to note that if the universal donor with type O blood has been previously exposed to the Rh antigen, Rh antibodies may be present in the donated blood. Additionally, introducing type O blood into an individual with type A, B, or AB blood will introduce antibodies against both A and B antigens from the type O plasma.
In a true life-threatening emergency situation where cross matching is not possible, type O blood can still be transfused to save a patient's life, even though it may cause some adverse effects due to the presence of antibodies.