(1) If anticoagulated venous blood is the specimen, fill a plain capillary tube with blood. If blood without anticoagulant is used, fill a heparinized capillary tube with the blood specimen. A heparinized capillary tube is identified by red line on the tube specimen. A heparinized capillary tube is identified by a red line on the tube.
(2) Allow blood to enter two capillary tubes until they are approximately 2/3 filled with blood. (Air bubbles denote poor technique, but do not affect the results of the test.
(3) Seal the unfilled ends of the tubes with clay.
(4) Place the two hematocrit tubes in the radial grooves of the centrifuge head exactly opposite each other, with the sealed end away from the center of the centrifuge.
(5) Screw the flat centrifuge head cover in place.
(6) Centrifuge at 10,000 rpm for 5 minutes.