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Blood
Laboratory |
Blood cell indices >
Hemoglobin content
determination |
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A common method
for measuring the hemoglobin content of blood
makes use of an instrument known as a
hemoglobinometer, which compares the colour of
light passing through a hemolyzed blood sample
with a standard colour. The results of the test
are expressed as grams of hemoglobin per 100 ml
of blood. |
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Procedure |
| Examine
the blood chamber below. It
consists of two pieces of glass and a
metal clip. Note that one of the pieces
of glass has an H-shaped depression cut
on it (the chamber glass), while the other piece is flat on
both sides (the cover glass). |
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A drop of
blood is placed on one side of the chamber glass. |
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The blood
is stirred with the end of a hemolysis
applicator until the blood appears as a
transparent red rather than a cloudy
liquid.
The hemolysis applicator has been dipped in a
solution of saponin, which destroys the integrity of the red cell
membrane, releasing the intracellular hemoglobin. |
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| The
cover glass is positioned on top of
the blood plate and both are slid into
the metal clip. The blood chamber is then
slid into the slot on the side of the hemoglobinometer, and a reading is taken. |
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This photo shows the hemolyzed blood layer
on the raised part of the glass chamber which is drawn slightly out of
the clip. The cover glass on top is already well seated in the clip. The
chamber glass with the blood sample will be pushed in completely: the
blood sample will thus be "sandwiched" between the two pieces of glass
and can be introduced in the hemoglobinometer. |
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When the blood chamber has
been filled with hemolyzed blood, it is inserted
in the slot on one side of the hemoglobinometer
as shown in the accompanying image (insert, upper
right). When the hemoglobinometer is held to the
eye, and the light switch button is depressed, a
green split field appears (insert, upper left).
To practice taking a reading, click below and
watch as the slide moves along, taking note of
the concentration (in Grams of Hb/100 ml) when
the two halves of the field appear to be the same
shade of green. |
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- You should
have obtained a value of 17 grams
Hb/100ml.
- Note that the
normal range of values for hemoglobin
content is as follows:
| Female: |
11.5-15.5 g /dl |
| Male: |
13.5-17.5 g/dl |
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To
continue to the next section: MCV and MCHC, click here |