Final answer:
The blood type consistent with negative reactions in reverse grouping with A1 and B cells, and positive reactions in forward grouping with A, B, and AB antigens, is AB positive.
Step-by-step explanation:
If reverse grouping showed negative reactions with A1 and B cells, and forward grouping showed positive reactions with A, B, and AB antigens, the blood type that is consistent with these results is type AB positive. When interpreting blood typing results, it is important to consider both the forward and reverse typing results. In forward typing, red blood cells are mixed with antibodies against A and B antigens (anti-A and anti-B), and agglutination (clumping) indicates the presence of the respective antigens on the cells. In reverse typing, the patient's serum is mixed with red blood cells that are known to express either A or B antigens, with agglutination indicating the presence of antibodies against those antigens in the serum.
In this case, the absence of agglutination in the reverse grouping with A1 and B cells suggests that there are no anti-A or anti-B antibodies in the serum, which is characteristic of someone with AB blood type. The positive reactions in the forward grouping with A, B, and AB antigens confirm that the individual's red blood cells carry both types of antigens, consistent with type AB blood. Since the Rh factor (positive or negative) is not specified in reverse typing, the positive response to AB antigens in forward typing would indicate that the Rh factor is positive, leading to the conclusion that the blood type is AB positive.