Final answer:
When performing a sed rate test, the Wintrobe or Westergren tube is filled to the level marked zero(0). This test involves measuring how quickly red blood cells settle in the tube, and the proper filling of the tube is essential for accurate results.
Step-by-step explanation:
When performing a sedimentation rate test, commonly known as a sed rate test, the Wintrobe or Westergren tube is filled to the level marked 0. The sed rate test measures how quickly erythrocytes, or red blood cells, settle at the bottom of the test tube which is filled with anticoagulated blood.
The difference in height between erythrocytes and the plasma after one hour is the sedimentation rate. The Wintrobe method uses a shorter, thicker tube, while the Westergren method uses a longer, thinner tube and is the recommended method because it is more sensitive.
In the context of the height examples provided, they reflect the readings from a manometer and not directly applicable to a sed rate test. Also, information about how to fill a test tube with a mixture is not related to the sed rate procedures. For the sed rate, correct tube filling is crucial to obtain an accurate measurement, as the test outcome is influenced by the height of the blood column.