A sample agglutinates in the anti-B and anti-D wells but not in the anti-A well. What is the type?

1. A bedside typing card has three wells, coated with anti-A, anti-B and anti-D antibodies. 2. Agglutination in a well means the matching antigen is present on the cells. 3. No reaction in the anti-A well means the A antigen is absent. 4. Agglutination in the anti-B well means the B antigen is present, so the ABO type is B. 5. Agglutination in the anti-D well means the Rh D antigen is present, so the Rh status is positive. 6. Combining the two gives B positive. 7. Reading agglutination as absence of the antigen inverts the whole test and produces A negative, which is why that option sits in the list. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 18 "The Cardiovascular System: Blood", section 18.6 Blood Typing_