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Instructions

Hematocrit is the amount of red blood cells that you have relative to your blood plasma. It is obtained by centrifuging a sample of blood and separating it into red blood cells and plasma. (Note, leukocytes and platelets form a thin buffy coat between the two). It is of interest because it tells the ratio of red blood cells to plasma which reflects your ability to deliver oxygen to cells. However, it does not tell you your total hemoglobin concentration. Typically men have a hematocrit between 42 and 54 while women have a hematocrit between 38 and 46.

There are several ways hematocrit is measured in the lab. We will be doing a simple way that can be done anywhere you have a ruler and a centrifuge. You take the blood sample and line it up on the ruler with the top of the clay plug at the 0. You then measure the red blood cells and the total blood volume in cM. So in the picture to the right, the male has a red blood volume of 4 cM and total blood volume of 8 cM. You then divide 4 by 10 and multiple by 100 % to get he has a hematocrit of 40 % which is a little low. For the female sample, you take the blood volume of 3.5 cM and divide it by 10 cM which is the total blood volume. This gives you 35 % which again, is low.

You will be doing this for 4 samples. 2 are normal for their sex and 2 abnormal. Drag the samples into the empty slot by the rule and record the red blood cell and total blood volumes on P 86 of your lab book to calculate their hematocrit. Then calculate the total hemoglobin. You will have to drag each sample back to its resting place. Also, note that there is no clay plug. I did this so the bottom lines up with 0

Ruler		Normal Female	Normal Male	Abnormal Female	Abnormal Male