The ABCs of Lab Testing Part 1

posted on December 07, 2015 by Dr. Jamie Hartman

There are a lot of acronyms used in the medical field.  One area where we use abbreviations frequently is with the blood work and laboratory tests we run.  In this three part series of blogs, we will look at some of the different abbreviations and acronyms we use so you can speak the lingo with us!

This first part of the series will focus on the CBC.  CBC stands for complete blood count.  It is a test that looks at the numbers, shapes, color, age, and types of red and white blood cells, as well as platelets.

Red blood cells or RBCs are used by the body to circulate oxygen, which is carried by hemoglobin.  A CBC also looks at hemoglobin amount.  Too low of a red blood cell count is called anemia.  Blood loss, lack of production, and increased consumption of red blood cells can all lead to an anemia.  Blood loss can occur from injuries (cuts, punctures), trauma, bleeding ulcers, nose bleeds, etc.  A lack of production is usually indicative of a bone marrow problem, or sometimes it can be seen with severe kidney disease.  Increased consumption can occur if there was a past bleeding event, or if there are tumors destroying blood cells, or in auto immune diseases affecting the red blood cells.  Checking a CBC yearly helps us determine if there is problem with the red blood cell numbers and can help us catch diseases earlier.

White blood cells respond to infections and inflammation in the body.  There are multiple types of white blood cells or WBCs.  Neutrophils or neuts, are seen in a recent infection, and are like first responders.  Lymphocytes or lymphs, are seen in response to infections as well, and are associated with immune system memory (i.e. how vaccines work).  Eosinophils or eos, are often seen in response to allergies or parasite infections.  Mast cells are seen with allergies, or mast cell tumors.  Lastly, macrophages are the clean up crew of the body-often cleaning up infection, dead cells, and bacteria.  By looking at the overall number of WBCs and the individual numbers of the different types, it can help us determine if illness is occurring and help us try to pinpoint a cause or source.  When an infection first starts, the WBC number in the blood may actually lower, as the WBCs circulating leave the blood stream to go to the sight of infection.  As the body responds, the WBC count should climb as more WBCs are produced to help fight the infection.  Tumors or bone marrow issues can affect WBCs as well.

Platelets are the clotting cells of the body.  They can be low when the body is using them, destroying them, or not producing enough.  If low, we often are concerned about immune mediated diseases or bleeding, which can be internal.  Some tick borne illnesses can cause low platelets too.  If too low, pets can start to bleed from every day activity or spontaneously.  Signs of low platelets can include bruising or bleeding.

Overall, the CBC gives us a good idea what is going on in the body.  Yearly to semi-annual monitoring of this along with a chemistry profile to look at organ function can help us recognize diseases early which can lead to faster treatment, better outcomes, and longer lives.  Next month we will discuss the chemistry profile a little more in depth.