Why Is My Dog Or Cat’s C-Reactive Protein Level High?

Ron Hines DVM PhD

See What Normal Blood & Urine Values Are

Causes Of Most Abnormal Blood & Urine Tests

See How Tests Are Grouped

Your Dog And Cat’s C-Reactive Protein Level = CRP

C-reactive protein is mainly produced in your dog or cat’s liver in response to inflammation or tissue damage anywhere in its body. It is one of the positive acute-phase proteins which all respond in this general way when your pet’s immune system’s macrophages and T-cells release pro-inflammatory cytokines. C-reactive protein blood levels go up within a matter of hours after inflammation begins. They slowly return to normal after the inflammation subsides. In healthy dogs, CRP levels are usually less than 20 mg/L (20 µg/ml). Within a matter of hours after infection or inflammation, CRP blood levels can rise to very high levels. The level generally peaks by the end of the first or second day – if the problem that caused the increase begins to be resolved. Less is known about the value of the CRP test in cats. A variety of inflammatory conditions also cause feline CRP to rise. Feline health issues that cause fever or an elevated neutrophil white blood cell count are most likely to do so. However, simple feline anxiety, so common at animal hospitals, will also cause a CRP elevation through a stress release of neutrophils into your cat’s circulation. The most common causes of high CRP levels in cats are probably abscesses and post incident cat fight septicemia, although it can also be the consequences of recent anesthesia, surgery, or another stressful event as well. As in dogs, CRP generally peaks at 24–48 hours after the event that caused it. But it will remain above normal as long as the inflammation that caused it persists. 

C-reactive protein values have been used to monitor many of the causes of infection and inflammation in people as well. You can read an e-brochure on its use in people here. The C-reactive protein test cannot tell you what the source of inflammation is or where in the body it is occurring. But it does confirm the presence of inflammation and that your pet truly has a health issue that needs to be addressed.

The C-reactive protein test offers your veterinarian a way to confirm progress and monitor the treatment of canine parvovirus infections,   pyometra or inflammatory bowel disease (IBD) in dogs. C-reactive protein also increases in dogs with cancer (read here) and autoimmune disease. It also rises in cases of bacterial infection, gum (periodontal) disease,   pancreatitis,   triad disease in cats,   arthritis and fat inflammation (panniculitis). C-reactive protein level also rises in major heartworm infections. (read here) Levels can also moderately increase in dogs during early pregnancy. Endocrine gland diseases or neurological diseases issues rarely cause an elevation in C-reactive protein level. (read here) Texas A&M University’s GI Lab offers this test as a way of measuring the severity of canine small intestinal disease.  Idexx Laboratories,   Antech/Mars and Cornell Veterinary School offer this test as well.  

As I mentioned, much less is currently known about the c-reactive protein test’s usefulness in cats. Perhaps it has some usefulness when monitoring or diagnosing FIP.  (read here)  

Elevated c-reactive protein levels in humans can be associated with obesity and unhealthy diets. (read here & here)

Running the c-reactive protein test on your pet periodically can give you and your veterinarian an indication whether the medications and treatments being provided to your pet are improving the condition for which it is being treated.

CRP values can be used much like a much older test, the erythrocyte sedimentation rate (ESR). The ESR test relies on increased blood levels of a different marker of inflammation, fibrinogen.


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