The hematocrit is a measurement of the percentage of packed red blood cells in the blood. Like the hemoglobin determination, the hematocrit may also be used to determine if an individual is anemic.

The normal range of values for a female is 36% to 46%. The normal range of values for a male is 38% to 50%. If the hematocrit of an individual is 45%, this indicates that 45% of his whole blood is red cells and 55% is plasma.

Exercise 26.5 Materials:

Cotton ball soaked in alcohol

Sterile disposable lancet

Heparinized (anti-coagulant) capillary tube

White plastic sealant

Hematocrit centrifuge

Hematocrit capillary tube reader

1. Scrub a finger with alcohol. Stick the finger with a sterile lancet. Immediately after using the lancet; place it in the bio-hazard container. Any disposable object contaminated with blood should be placed into the bio-hazard container.

2. The heparinized capillary tube has a black ring approximately 1/2"from one end of the tube. The end of the heparinized capillary tube farthest away from the black line should be placed into a drop of blood on the end of your finger. Place the heparinized capillary tube into the blood at an angle slightly above horizontal Capillary action will pull the blood into the heparinized capillary tube. Fill the tube to the black line.

3. Remove the plastic covering from the sealant; seal the end of the heparinized tube that was placed into the blood by pushing it into the white plastic sealant.

4. Place the heparinized capillary tube into the hematocrit centrifuge with the sealed end of the heparinized capillary tube against the rubber-cushioned end of the centrifuge slot.

5. Your instructor will operate the hematocrit centrifuge.

6. After the hematocrit centrifuge has spun for approximately four minutes, your instructor will demonstrate the technique necessary to read the heparinized capillary tube using the hematocrit capillary tube reader.

7. Place your heparinized capillary tube into the bio-hazard container.

8. Record your hematocrit reading below.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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  • john donaldson
    What is in the hematocrit tube with black ring?
    6 years ago

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