Final answer:
A yellow top tube is used for various tests, often related to microbiology, DNA, and genetics, and is sent to corresponding lab sections. For blood typing, agglutination with both anti-A and anti-B antibodies indicates type AB blood. In emergencies, O negative blood is transfused due to its universal donor status.
Step-by-step explanation:
When a yellow top tube is used for blood collection, it typically contains either ACD or SPS anticoagulants. The tests run on these samples can include blood cultures for microbiology, DNA testing, and various other immunohematology and genetic tests.
These samples are usually sent to the laboratory section appropriate for the specific test ordered, such as the microbiology lab for cultures or the genetics lab for DNA analysis. In the case of a blood typing test, visibly agglutinated blood in the presence of anti-A and anti-B antibodies indicates a normal response for blood type AB. This is because the presence of both types of antibodies in the agglutination test suggests that the patient's blood type has both A and B antigens, hence being typed as AB.
In emergency situations, such as the case of a severe accident where there is no time for blood typing, patients are typically transfused with O negative blood, since it lacks A, B, and Rh antigens, reducing the risk of adverse reactions that could occur with other blood types. Thus, it is considered the universal donor and is safe for initial emergency transfusions. A cross-match assay would later be performed to ensure compatibility for further transfusions.