Final answer:
Blood should not be drawn from a patient who is standing due to the risk of syncope. In urgent situations where the patient's blood type is unknown, Type O negative blood is used, and antibody screenings are crucial to prevent transfusion reactions. Blood typing tests that show agglutination in both anti-A and anti-B antibodies indicate AB blood type.
Step-by-step explanation:
Blood should not be drawn from a patient who is standing due to the increased risk of fainting or syncope. When a patient is standing, the circulatory adjustments needed for a venipuncture may cause a sudden drop in blood pressure, leading to dizziness or fainting which can lead to injury.
As for the other responses, being nervous, unable to make a fist, or not fasting are not standard contraindications for drawing blood, although they may present challenges or affect certain test results. For example, fasting may be required for certain laboratory tests to ensure accuracy, such as lipid panel or fasting blood sugar levels.
Case Scenarios:
- In a severe bleeding case like a motor vehicle accident where the patient's blood type cannot be determined quickly, universal donor blood (Type O negative) is typically transfused due to the absence of A, B, or Rh antigens, reducing the risk of transfusion reactions.
- If a blood type test shows agglutination in both anti-A and anti-B antibodies, it indicates that the patient's blood type is AB positive or negative, which is a normal response for someone with that blood type, not necessarily a technician error.
- A patient arriving in the emergency department with low blood pressure and complaining of thirst could be experiencing hypovolemic shock, possibly due to dehydration or bleeding, requiring immediate medical attention.
- Antibody screening tests are essential in pretransfusion protocols to ensure that the recipient is not making antibodies against antigens outside of the ABO or Rh systems, which may lead to a transfusion reaction.