Red Blood Cell (Erythrocytes) Count and Hematocrit
|Why is this test done?||Red blood cell count and hematocrit are part of a complete health check. These tests results make it possible to evaluate blood cell production for proper functioning or identify various red blood cell imbalances. Hematocrit gives information about the hydration status of the body.|
|How to prepare:||
|Associated Tests:||Other tests that are part of the complete blood count are done at the same time. These include various parameters such as hemoglobin levels, complete white blood cell count , platelet count , differential white blood cell count and physical characteristics of red blood cells.|
Red blood cells ensure oxygen transport in the blood. When their number decreases, oxygen levels decrease and certain body functions may be affected. But if their number is to high, blood becomes thicker and flows less freely. Hematocrit corresponds to the ratio of the percentage of the blood volume occupied by red blood cells in total blood volume. Hematocrit is function of the number, volume and blood level of erythrocytes.
What does an abnormal test result mean?
If the result is to high
Certain anomalies can cause red blood cell count to increase (polycythemia) by increasing red blood cell production in bone marrow.
If the result is to low
Red blood cell count will be lower if there is a major loss of blood (hemorrhage), anemia, or red blood cell destruction. Certain cancers (leukemia, multiple myeloma, Hodgkin's disease) as well as lupus, endocarditis, malnutrition and certain kidney diseases can also lower red blood cell count and hematocrit.
Red blood cell count and hematocrit results cannot be interpreted by themselves. The results of other tests performed at the same time are important as well and are taken into consideration to determine the possible cause of any abnormal results.
Factors that can affect the result of the test
Staying in high altitude or in an oxygen-poor setting will increase red blood cell production by the bone marrow. Smoking, a polluted environment or dehydration also increases red blood cell count and hematocrit.
Increased plasma volume in the blood will make red blood cells appear to be less numerous (hemodilution effect). This is often seen in pregnancy, with hyperhydration or malnutrition.
From the puberty, the red blood cells count is lower in women because of the menstruations.
What you need to know before the test
Before going for blood tests, a procedure or other exam, it is best to always bring a list of all the drugs you take (prescription, OTC and natural health products). Unless told otherwise, you should take your medication as usual on the day of the test. When in doubt, ask your pharmacist for more information.
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The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.