Times change and my website needed to change too. To see the 2020 update of this page click this link
To see what normal blood and urine values are, go here
For an explanation of causes of most abnormal blood and urine tests, go here
To see how tests are grouped, go here
The amount of protein circulating in your dog or cat's blood serum tells your vet a lot of things. For one, it can be a clue as to how well your dog or cat is hydrated. It can also tell your veterinarian a lot about how well your pet’s liver and kidneys are functioning. When we we do calculations to known the amount of albumen protein within the total protein fraction and subtracted that from the TP, it gives your pet's globulin protein level. Low or high blood globulin can alert your veterinarian to chronic inflammation or infectious disease that may be present somewhere in the body.
The blood of your dog or cat contain a large number of other dissolved specialized proteins in smaller amounts. Some of them transport vital nutrients to cells. Others function as hormones or antibodies that protect against disease. But the majority (~55%) of your pet’s blood protein is albumin –the same protein that makes up much of the egg whites you eat. Albumin is produced by your pet’s liver. It helps keep your pet’s blood pH in a narrow optimal range, it binds to many hormones allowing them to circulate throughout the body and it helps keep fluids in their proper location (osmotic effect).
When your pet is severely deficient in total protein, fluid will leak into the space surrounding its lungs (pleural effusion) and abdominal organs (ascites). Respectively, that causes difficulty breathing or a potbelly.
The next most prevalent proteins in your pet’s blood forming part of the TP are globulins (~38%). Some is produced in your pet’s liver and some (the immunoglobulins or antibodies) are made by portions of your pet’s immune system ( the lymphoid tissue).
The third most prevalent blood protein included in TP is fibrinogen (~ 5%). Fibrinogen converts to fibrin which is required for your pet's blood clotting process. If the laboratory is checking your pet's blood serum after the blood has clotted (a red top tube) , fibrinogen will not be included in your pets total protein level (it is all in the clot at the bottom of the test tube). If the test was performed on whole blood plasma (a purple top tube) the TP number will be a bit higher because the fibrinogen is still present.
Since blood protein is mostly a combination of albumin and globulin, two different groups of health issues will make your pet's TP level go up or down. One relates to the amount and fate of the albumin (and certain globulins) produced by your pet’s liver and the other to its immune system and antibody function.
Though not a disease, the most common reason a pet’s TP level might be elevated is dehydration. That could be due to a failure to drink, chronic diarrhea, vomiting or perhaps a prolonged fever.
The second most common reason for high total protein is stimulation of your pet’s immune system to make globulin-containing antibodies. Infections and chronic inflammations are the most likely cause.
Most veterinary blood chemistry determinations report immune globulin values separately from total protein - although the TP value includes globulin as well.
Just as for abnormally high total protein levels, abnormally low TP values can be due to either a low albumin or a low globulin protein portion or both.
A common cause in younger dogs is a heavy hookworm infection. Heavy flea infestations in puppies and kittens - often accompanied by malnutrition is another common cause.
In mature dogs, chronic intestinal inflammation (protein-loosing enteropathies), such as IBD, certain food sensitivities (malabsorption syndromes) or pre-lymphoma states (primarily in cats) will also allow blood proteins to leak out of the body through the intestine.
Dogs and cats with chronic liver and pancreatic problems (triad disease/cholangiohepatitis) also tend to have low TP levels.
Pets not getting enough high quality protein in their diet is another potential cause of low blood protein levels in dogs and cats.
Pet with extensive liver damage no longer have the ability to manufacture sufficient albumen. So their TP levels are usually low.
Blood protein can also be lost when it is incorporated in abnormal fluids that sometimes pool in the chest and abdomen of dogs and cats in heart failure. It is probably also due to poor circulation within their livers where albumin and some globulin is made.
Losses of large amounts of blood due to trauma will also deplete your pet’s blood protein stores.
TP level can also drop in acute infections and inflammation when those issues cause chemicals called cytokines to be released into the dog or cat’s circulation (a negative acute phase response).
Loss of large amounts of blood serum containing albumen and globulins through burns, wounds and extensive skin infections (such as sarcoptic mange) can also lower TP. In demodectic mange, it is the globulin portion that might be low.
Puppies and kittens tend to naturally have moderately lower TP levels because they are not yet producing globulin antibodies at the level that mature pets do.
All the causes I listed for low blood albumin levels will also cause low TP levels.