Although the hemoglobin content of a blood sample can be measured in several ways, a common method uses a hemoglobinometer. This instrument is designed to compare the color of light passing through a he-molyzed blood sample with a standard color. The results of the test are expressed in grams of hemoglobin per 100 mL of blood or in percentage of normal values.
1. To measure the hemoglobin content of a blood sample, follow these steps:
a. Obtain a hemoglobinometer and remove the blood chamber from the slot in its side.
b. Separate the pieces of glass from the metal clip and clean them with 70% alcohol and lens paper. Note that one of the pieces of glass has two broad, U-shaped areas surrounded by depressions. The other piece is flat on both sides.
c. Obtain a large drop of blood from a finger, as before.
d. Place the drop of blood on one of the U-shaped areas of the blood chamber glass.
e. Stir the blood with the tip of a hemolysis applicator until the blood appears clear rather than cloudy. This usually takes about 45 seconds.
f. Place the flat piece of glass on top of the blood plate and slide both into the metal clip of the blood chamber.
g. Push the blood chamber into the slot on the side of the hemoglobinometer, making sure that it is in all the way (fig. 39.2).
h. Hold the hemoglobinometer in the left hand with the thumb on the light switch on the underside.
i. Look into the eyepiece and note the green area that is split in half.
j. Slowly move the slide on the side of the instrument back and forth with the right hand until the two halves of the green area look the same.
k. Note the value in the upper scale (grams of hemoglobin per 100 mL of blood), indicated by the mark in the center of the movable slide.
l. Record the test result in Part A of the laboratory report.
2. Complete Part C of the laboratory report.
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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.