This is to demonstrate how to measure packed cell volume. And this is the equipment that you will need-- PCV centrifuge, microhematocrit reader, clay sealant, micro-centrifuge capillary tubes, glass waste container, selection of gloves, and, of course, your blood sample-- in this case, collected in potassium EDTA tube kept in the fridge until before this demonstration. For this procedure, you would always wear gloves of an appropriate size. Your blood sample will have been kept in the fridge. And if it's been kept upright for some time, it may mean that some of the cells have settled. So in order to get a good homogeneous sample, you rotate your tube slowly a number of times, about up to 12. This blood sample is actually in potassium EDTA. What we have here is capillary tubes, are glass. They have a blue ring at the end, which shows that they're plain tubes, as opposed to a heparinized. We need two of them at least, always in pairs, so that you can balance in a centrifuge machine. Place this in the blood. You can see that the blood is starting to move up the tube in a capillary action. You want at least 2/3 to 3/4 full. If we can't get it by an upright tube, turning a tube almost to horizontal will give you the amount you need. Hold the tube, place your finger over the end gently to create a vacuum. Place it in the clay sealant. Don't push down with your index finger, because the glass is very delicate. Twirl it around if you need to. And you should have a good clay sealant plug of several millimeters. Do the same again with the second tube. Place it in the sample. Once again, you can see capillary action. Not as high as we'd like it to be. Turn it sideways, and blood comes up to 3/4. Place your finger over the end of the tube. Create another vacuum. Clean the blood off this outside. Place in the clay sealant. You've now created a plug at the end. And take your finger off, twirl it around, if you need to. And you should have another good plug. Place the lid on the blood. We're now ready to centrifuge these. Pull the lid. This is a retaining lid-- very important not to forget this. Get rid of these samples. In here, it's important to check whether or not this rubber ring surround is in position. And then, you can place your samples in. You place them so that the clay plug is towards the outside against this rubber seal, and the same diametrically opposite. You can have as many samples as you like to fill up all these spaces, but they must be in pairs and balanced. This lid, again, replaced in order to keep these samples in position. The outer lid is placed down. There, sealed. Switch on. We want it on Fast for blood. And we can have it on for about, say, 5 minutes. [WHIRRING] Allow the machine to stop completely before you attempt to open the lid. Unscrew the lid. And see, you have two samples here, and good samples, actually. You see that you have a plasma layer, which is a straw color-- what you call the buffy layer, which is like a block of white cells and platelets there, mostly platelets-- and then, red blood cells here and a good plug in place there. So that's the first sample and the second sample, which should match it as well. So, two good samples there. And then, you read your percentage PCV, which is a movable section. Place this on the reader, like so. And we're measuring percentage, so we have naught percent there, and 100% there. These lines feed back, as you can see. And so what we want to do is to have the bottom of the sample-- the very bottom of the red blood cells, but before the clay plug-- on the zero line, and the top of the sample you can see is movable. So you want the very top of the sample on the 100% line right in the middle, like so. I have a movable gauge, here. And we take it just at the top of the red blood cell line. And that gives you a reading of about 46%. When you're finished, take your samples, dispose of them in glass waste. Lid back on, this lid down, switched off at the mains. Remove your gloves, and dispose.