What is a hematology lab test CBC for?

January 6, 2010

A hematology lab test for CBC or a Complete Blood Count test could be done for a variety of reasons. A high white blood count could be an indication of infection, and it also shows an increase in some types of leukemia. On the other hand low white blood counts could indicate bone marrow diseases or enlargement of the spleen. In some cases of HIV infection too, there may be a low white blood count.

The hemoglobin (Hgb) and Hematocrit (Hct) levels are also important factors. Hemoglobin refers to the amount of protein that carries oxygen and is present with the red blood cells, while hematocrit refers to the percentage of red blood cells in the context of volume occupied in the blood. In almost all laboratories the levels of hemoglobin are actually measured, but hematocrit levels are on the other hand computed based on red blood cell counts and Mean Corpuscular Volume or MVC measurements. The hemoglobin measurement is therefore usually treated as more reliable and a low Hgb or Hct measurement could be indicative of anemia, which may be a result of nutritional deficiencies, loss of blood, internal destruction of blood cells, or even an inability to produce blood normally in the bone marrow. Lung disease, residing in areas at a high altitude or even an excessive production of blood cells could cause high hemoglobin readings.

Another calculation or finding from the Complete Blood Count test would be the Mean Corpuscular Volume or MCV. This measurement helps in making a diagnois of anemia, as low values suggest the presence of an iron deficiency, while high values suggest the presence of B12 or Folate deficiencies, ineffective blood production within the bone marrow, or possible blood loss recently that has been replenished with newer cells from the bone marrow.

The Platelet Count or PLT is another measurement that is gauged and is a measure of the cells that, to put it simply – plug up the openings in blood vessels, preventing bleeding. High readings of platelet can occur when there has been bleeding, excess production in bone marrow, or also because of smoking. Low values on the other hand may be resultant from premature destruction states like acute blood loss, as an effect of certain drugs, due to Immune Thrombocytopenia, infections with sepsis, bone marrow failure, or leukemia. A low platelet count could also be indicative of entrapment of platelets within an enlarged spleen.

Submitted by M T on January 6, 2010 at 09:04

Read more questions in Blood Tests