The red blood cell indices are used to determine the size of the erythrocyte
and the hemoglobin content of the red blood cells, and to identify specific
types of anemia. The indices are not individual blood cell tests, but are the result of applying mathematical formulas to the hemoglobin value, hematocrit value, and red blood cell count. Each index has its own formula that is automatically computed as a part of the complete blood count.
Red blood cell indices include the mean corpuscular volume, which
describes the average volume (size) of an individual red blood cell; the
mean corpuscular hemoglobin, the average weight of the hemoglobin in
an average red blood cell; and the mean corpuscular hemoglobin concentration,
which is the average concentration or percentage of hemoglobin
within each red blood cell.
and the hemoglobin content of the red blood cells, and to identify specific
types of anemia. The indices are not individual blood cell tests, but are the result of applying mathematical formulas to the hemoglobin value, hematocrit value, and red blood cell count. Each index has its own formula that is automatically computed as a part of the complete blood count.
Red blood cell indices include the mean corpuscular volume, which
describes the average volume (size) of an individual red blood cell; the
mean corpuscular hemoglobin, the average weight of the hemoglobin in
an average red blood cell; and the mean corpuscular hemoglobin concentration,
which is the average concentration or percentage of hemoglobin
within each red blood cell.
Mean Corpuscular Volume (MCV)
The mean corpuscular volume describes the average size of an individual
red blood cell in cubic microns (Fim3), and is calculated by multiplying the
hematocrit percentage by 10, and then dividing that result by the red blood
cell count. The size of red blood cells can have clinical significance in various
types of anemia.
red blood cell in cubic microns (Fim3), and is calculated by multiplying the
hematocrit percentage by 10, and then dividing that result by the red blood
cell count. The size of red blood cells can have clinical significance in various
types of anemia.
Normal Range
Adults and Children
80-95 gm3
Newborns
96-108 ~Lm3
80-95 gm3
Newborns
96-108 ~Lm3
Variations from Normal. When there is a decrease in the mean corpuscular
volume, the erythrocytes are microcytic, or smaller than normal. Microcytic
red blood cells are seen in iron deficiency anemia, lead poisoning,
and thalassemia .
An increase in the mean corpuscular volume indicates that the red
blood cells are macrocytic, or larger than normal. Pernicious anemia is associated
with macrocytic red blood cells.
When the mean corpuscular volume is within normal range, the red
blood cells are normocytic, or of normal size. Aplastic, hemolytic, and temporary
blood loss anemia are associated with red blood cells that are normal
in size.
volume, the erythrocytes are microcytic, or smaller than normal. Microcytic
red blood cells are seen in iron deficiency anemia, lead poisoning,
and thalassemia .
An increase in the mean corpuscular volume indicates that the red
blood cells are macrocytic, or larger than normal. Pernicious anemia is associated
with macrocytic red blood cells.
When the mean corpuscular volume is within normal range, the red
blood cells are normocytic, or of normal size. Aplastic, hemolytic, and temporary
blood loss anemia are associated with red blood cells that are normal
in size.
Mean Corpuscular Hemoglobin (MCH)
The mean corpuscular hemoglobin is the average weight of hemoglobin
in an average red blood cell. This weight is calculated by multiplying the hemoglobin count by 10 and then dividing by the red blood cell count.
The result is reported in picograms (pg). The mean corpuscular hemoglobin
is adequate for diagnosing severely anemic patients, but is a nonspecific
result.
in an average red blood cell. This weight is calculated by multiplying the hemoglobin count by 10 and then dividing by the red blood cell count.
The result is reported in picograms (pg). The mean corpuscular hemoglobin
is adequate for diagnosing severely anemic patients, but is a nonspecific
result.
Normal Range
Adults and Children
27-31 pg
Newborns
32-38 pg
Adults and Children
27-31 pg
Newborns
32-38 pg
Variations from Normal. An increase in the mean corpuscular hemoglobin
is seen in macrocytic anemia, while a decrease is associated with microcytic
anemia .
is seen in macrocytic anemia, while a decrease is associated with microcytic
anemia .
Mean Corpuscular Hemoglobin Concentration (MCHC)
The mean corpuscular hemoglobin concentration measures the average
concentration or percentage of hemoglobin within each red blood cell. The
MCHC is calculated by dividing the hemoglobin value by the hematocrit
value, and multiplying the result by 100. The mean corpuscular hemoglobin
concentration is most valuable for classifying anemias.
concentration or percentage of hemoglobin within each red blood cell. The
MCHC is calculated by dividing the hemoglobin value by the hematocrit
value, and multiplying the result by 100. The mean corpuscular hemoglobin
concentration is most valuable for classifying anemias.
Normal Range
Adults and Children 32-36%
Newborns 32-33%
Adults and Children 32-36%
Newborns 32-33%
Variations from Normal. A decrease in the mean corpuscular hemoglobin
concentration indicates that the red blood cells contain less hemoglobin
than normal and is classified as hypochromic anemia, which means the red
blood cells lack color. Iron deficiency anemia is the most common type of
hypochromic anemia .
An increase in the mean corpuscular hemoglobin concentration usually
indicates spherocytosis . Spherocytosis is defined as an increase in the
number of abnormal, spheric, red blood cells called spherocytes. Sphero
cytes have a smaller amount of membrane and a full complement of hemoglobin
so the mean corpuscular hemoglobin concentration is elevated.
Table 1-2 lists the classifications of anemia based on the red blood cell indices
values.
concentration indicates that the red blood cells contain less hemoglobin
than normal and is classified as hypochromic anemia, which means the red
blood cells lack color. Iron deficiency anemia is the most common type of
hypochromic anemia .
An increase in the mean corpuscular hemoglobin concentration usually
indicates spherocytosis . Spherocytosis is defined as an increase in the
number of abnormal, spheric, red blood cells called spherocytes. Sphero
cytes have a smaller amount of membrane and a full complement of hemoglobin
so the mean corpuscular hemoglobin concentration is elevated.
Table 1-2 lists the classifications of anemia based on the red blood cell indices
values.
Erythrocyte Sedimentation Rate (ESR, Sed Rate)
The erythrocyte sedimentation rate is the rate at which red blood cells settle
out of unclotted blood in an hour. The results are expressed as millimeters
per hour (mm/hr). This is a nonspecific test because it does not identify any
particular disease. In fact, the ESR can be normal in many disease processes.
The erythrocyte sedimentation rate is useful in determining the
progress of inflammatory diseases, rheumatoid arthritis, rheumatic fever,
and acute myocardial infarction. The speed at which the red blood cells fall
to the bottom of the test tube corresponds to the degree of inflammation.
out of unclotted blood in an hour. The results are expressed as millimeters
per hour (mm/hr). This is a nonspecific test because it does not identify any
particular disease. In fact, the ESR can be normal in many disease processes.
The erythrocyte sedimentation rate is useful in determining the
progress of inflammatory diseases, rheumatoid arthritis, rheumatic fever,
and acute myocardial infarction. The speed at which the red blood cells fall
to the bottom of the test tube corresponds to the degree of inflammation.
Normal Range
Men <50 yrs 0-10 mm/hr
>50 yrs 0-13 mm/hr
Women <50 yrs 0-13 mm/hr
>50 yrs 0-20 mm/hr
Children 0-10 mm/hr
>50 yrs 0-13 mm/hr
Women <50 yrs 0-13 mm/hr
>50 yrs 0-20 mm/hr
Children 0-10 mm/hr
Variations from Normal. An increase in the sed rate is usually due to inflammation
or tissue injury. When sed rates are greater than 100 mm/hr,
likely causes, except in pregnancy, are infections, malignancies or collagen
vascular diseases. A decrease in the sed rate is associated with polycythemia
vera, sickle cell anemia, and a deficiency in the plasma protein fibrinogen.
or tissue injury. When sed rates are greater than 100 mm/hr,
likely causes, except in pregnancy, are infections, malignancies or collagen
vascular diseases. A decrease in the sed rate is associated with polycythemia
vera, sickle cell anemia, and a deficiency in the plasma protein fibrinogen.
Interfering Circumstances. Many factors can influence the erythrocyte sedimentation
rate. Refrigerated blood samples, blood left standing for more than two hours before the test, menstruation, and pregnancy will cause a
nonpathological increase in this test. Age and certain drug therapies may
also cause variations in test results .
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