Final answer:
Filling blood collection tubes with the correct volume is crucial because underfilling can cause dilution with anticoagulants, affecting test results. Within an hour in a tube, serum is separated from clotted cells. The agglutination of a patient's blood with both anti-A and anti-B antibodies indicates a blood type of AB.
Step-by-step explanation:
It is important to fill the collection tubes with the correct volume of blood because underfilling can lead to sample dilution with the anticoagulant. When a blood collection tube is not filled to the intended volume, the proportion of anticoagulant (or any other additive) is higher relative to the blood volume. This can interfere with the test results as the blood sample is not in the balance it was intended to be when the tube was designed.
Overfilling a tube, on the other hand, can be problematic, but typically does not lead to sample dilution. Instead, overfilling might lead to issues such as tube breakage or inaccurate ratios of additives, but is less common as the tubes are often designed with some excess capacity to account for slight overfilling.
During the hour a blood sample is left in a glass tube, the blood will clot if the tube does not contain an anticoagulant, and the serum is separated from the clotted cells. Serum is the liquid portion of blood that does not include the coagulation factors, which are consumed in the clotting process.
If both anti-A and anti-B antibodies cause agglutination, this indicates that the patient has blood type AB, which is a normal reaction for individuals with this blood type. The lab technician has not made an error in observing both samples agglutinate.