EVALUATION OF ERYTHROCYTES

3 EVALUATION OF ERYTHROCYTES



Shannon Jones Hostetter, Claire B. Andreasen



1 What are the major red blood cell indices used to characterize anemia in dogs and cats?



a. Mean corpuscular volume (MCV) is a measure of the size of the average erythrocyte and is measured in femtoliters (fl).

b. Mean corpuscular hemoglobin concentration (MCHC) is a measure of the concentration of hemoglobin in the average packed cell volume (PCV) unit and is expressed as grams per deciliter (g/dl).

c. Red cell distribution width (RDW) is a measure of the degree of size variation in erythrocytes (anisocytosis) and is expressed as a percentage.


2 List some factors that influence the mean corpuscular volume.



a. Young animals tend to have smaller erythrocytes and a corresponding low MCV.

b. MCV is most often increased as a result of reticulocytosis.

c. Microcytosis, or decreased MCV, can be seen in animals with portosystemic shunts.

d. Iron deficiency causes decreased MCV.

e. Macrocytosis, or increased MCV, has been described in cats infected with feline leukemia virus (FeLV).


3 What are some causes of hyperchromasia (increased MCHC)?



a. Absolute increases in MCHC, or actual increased hemoglobin within erythrocytes, are not usually observed and often are artifactual.

b. Intravascular or in vitro hemolysis is the most common artifact that causes increased MCHC.

c. Hyperlipidemia or Heinz bodies may cause falsely increased hemoglobin concentration due to interference.

d. Spherocytosis


4 What are some causes of hypochromia (decreased MCHC)?



a. Reticulocytosis leads to hypochromia (decreased MCHC.)

b. Iron deficiency can cause hypochromia.


5 How is new methylene blue used in erythrocyte evaluation?


New methylene blue is a stain used to identify the residual ribonucleic acid (RNA) in the cytoplasm of reticulocytes. Reticulocytes and Heinz bodies are accurately identified with this stain (see Figure 1-1).

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Aug 26, 2016 | Posted by in INTERNAL MEDICINE | Comments Off on EVALUATION OF ERYTHROCYTES

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