Final answer:
The sedimentation rate test measures how quickly red blood cells settle in a test tube and should be performed with anticoagulant to prevent clotting, which might interfere with the test.
Step-by-step explanation:
The sedimentation rate, or "sed rate," is a blood test that measures how quickly red blood cells settle at the bottom of a test tube.
The correct answer to the question is a. With anticoagulant. This is because the test requires a blood sample that does not clot, as clotting would interfere with the ability to measure the rate at which red blood cells settle. It's important to remember that rapid sedimentation of blood cells is not typical in a healthy body, but in certain diseases, blood cells can clump together, making these clumps heavier and causing them to settle more quickly. These insights into the sed rate can provide valuable information for diagnosing and monitoring various medical conditions.