A crucial set of tests to determine if an animal is ill is a blood panel. This panel gives us an indication of a pets internal health, and allows us to monitor disease processes and their treatments. It must be understood that each individual lab has its own set of normal values, which are based on that old bell shaped statically curve we all learned to love (and hate) in school. As a general summary, if one of your pets values falls outside of the range for this lab, it does not necessarily mean there is something wrong with your pet on that specific test. Also, it is necessary to follow the blood panel over a series of time to see which direction the trends are following. Finally, we do not interpret blood panels by themselves, we use all of the information available to us in regards to the diagnostic process.
The first part of the blood panel is called a CBC, which stands for complete blood count. It is a measure of an animals white blood cells (WBC's) and red blood cells (RBC's). In measuring the RBC's we are looking for a low count, called anemia, and a high count, called polycythemia. Of the two, anemia is much more common, so we will base our explanation on this problem only. Also, anemia is not a disease, it is a potential sign of a disease.
The RBC's are measured with 3 different tests. These are the RBC count, hematocrit, and hemoglobin. The RBC's are counted with a machine that gives us an actual number, usually in the millions per cc. Hematocrit is a percent of the red blood cells in the serum, usually near 45% (this varies tremendously with the species). Finally the amount of hemoglobin is determined. All 3 numbers are used in a determination of anemia. If anemia is present, other tests are used to determine if the anemia is regenerative or non-regenerative. In regenerative anemia's the body is making more red blood cells to make up for the anemia, in non-regenerative it is not. This is an important point from the diagnostic point of view because certain diseases tend to be one or the other.
The other part of the CBC is the analysis of the white blood cells, and is closely tied to the immune system. The total number of WBC's are noted, giving us an overall indication if a problem might exist. An elevated WBC count can be caused by inflammation, infection, or cancer. A low WBC count can be caused by a virus, an immunosuppressive disease, or a problem with the bone marrow. After the total WBC is determined the WBC's are broken down into their different types. These different types all have unique functions in the normal processes of the body. Changes in the amounts of these different types, whether or not the WBC count is normal, high, or low, also gives us important information.
The next part of the blood panel is called the chemistry panel (chem panel), also called the biochemistry panel (bcp). It tends to leave the white and red blood cells alone, and focuses more on the internal organs (although the two are closely related and not easily distinguished in this way-but that's the art of medicine). It is an automated test that checks many biological functions whether they are helpful in diagnosis or not. In some species, even though the tests are included in the chem panel, they might be useless in determining whether a pet has a disease or not. a good example of this is the kidney function test called BUN (blood urea nitrogen). This test is critical in diagnosing kidney problems in mammals (including humanoids), but is useless in birds and reptiles.
In general, the chem panel checks internal organs like the liver and kidneys. It also checks the general health of the body by measuring parameters like protein, glucose, and calcium. Interpretation of problems in the chem panel is very complex, and must be interpreted in conjunction with the other parameters of the diagnostic process.
Some of the tests in the chem panel measure internal organs directly, while others measure them indirectly. These tests are interpreted in conjunction with the CBC since the two are so closely related. For example, if a pet has anemia, and the liver tests are significantly elevated, all other things being equal, it is probable that the anemia is caused by a liver problem. It is not this simple though, because an anemic pet with normal liver tests can still have a liver problem as the cause of the anemia. Obviously, a normal chem panel is highly advantageous, although it is no guarantee that a pet is disease free.
We routinely perform 2 different blood panels. The first, called the pre anesthetic blood panel, is performed in our hospital. The second, called the Standard Blood Panel, is sent to our outside lab:
In House Pre anesthetic Blood Sample
This blood sample is performed in our own hospital's laboratory. From the time we take the sample until we get results is less than 30 minutes. It is used for young pets, apparently healthy pets, and for routine surgeries like spays, neuters, and declaws.
Organs that are important for the metabolism of the anesthesia we will be administering are targeted. Five specific areas are monitored:
- Red blood cells (RBC's) to check for anemia, proper oxygen carrying capacity of the red blood cells, and adequate clotting.
- White blood cells (WBC's) to look for signs of infection, inflammation, or cancer
- A protein test to check for dehydration, overall health status, and to help assess the liver
- A specific kidney test to check for proper kidney function
- A specific liver test to check for proper liver function
To run these tests we take less than a teaspoonful of blood from your pet. This blood is put into 2 separate test tubes for analysis. The first set of tests is performed with our QBC machine, the second set with our serum chemistry analyzer.
It is called a lavender top tube because it has chemicals (Ca EDTa) in it to prevent clotting of the RBC's. If the RBC's clot, we cannot count them.
The unclotted RBC's are siphoned from the lavender top tube and placed into a special tube that is used by our QBC machine.
The 48.3 is a measurement of the percent of RBC's in the blood stream.
The 345 is a measurement of the platelets.
The 10.1 is a measurement of how many WBC's are present in the bloodstream.
The other numbers break down the WBC's into different components and gives us information on the duration of infection (if there is an infection), the type of infection, and if there are any other problems besides infection or inflammation.
This is the other tube the original blood sample is placed in. This blood clots, allowing us to analyze the serum. This tube is called a serum separator tube because it separates the serum from the RBC's when placed in a high speed centrifuge.
This is what the serum separator tube looks like after 5 minutes in the high speed centrifuge. There are 3 distinct bands visible. At the very bottom are the clotted RBC's, above that is the separator between the RBC's and the serum, and the fluid that remains on the top is the serum.
Standard Blood Panel
The standard blood panel, made up of a CBC (complete blood count) and BCP (biochemical profile), is a thorough test of many of your pet's internal functions. It is much more thorough than the in house pre anesthetic blood panel, and consists of over 40 different parameters of internal health. Our standard blood panel routines includes a thyroid test, along with a heartworm test in dogs, and FeLV and FIV tests in cats.
This blood panel is used for pets that seem ill, for older (geriatric) pets, for pets that have a problem discovered during an exam, or when your doctor feels he or she needs a blood panel that is more thorough than the in house pre anesthetic blood panel. In general, this test is one of the most important ones your doctor can order because it gives us a large amount of information regarding your pet's internal status.
It is sent to one of our outside laboratories that maintain a high level of quality control by using highly automated and advanced laboratory equipment. The results of any blood panel submitted to this lab are faxed to us within 12-24 hours in most cases.
This test is used in conjunction with the standard blood panel. Its main goal is to assess the urinary tract (kidneys, ureters, and urinary bladder).
