Why Is My Dog Or Cat’s ANA Test Positive?

Why Is My Dog Or Cat’s ANA Test Positive?

Ron Hines DVM PhD

See What Normal Blood & Urine Values Are

The Causes Of Most Abnormal Blood  & Urine Tests

See How Tests Are Grouped

Anti-nuclear Antibody = ANA, ANF

This test measures factors similar to the Coombs test – evidence that your dog or cat is producing antibodies against its own tissue (In this case, antibodies against components of the nuclei of its cells). These are called autoimmune reactions. In humans, many of the conditions that produce ANA antibodies are lumped together as forms of “lupus”.

As pets and people age, the number of these self-directed blood antibodies moderately increase in all of us. (read here)

Health Problems That Might Increase ANA Levels In Your Pet:

The ANA test is quite sensitive – but it is not specific for any one disease. It can only used as one factor your veterinarian will consider in making an autoimmunity diagnosis. ANA is often elevated in:
Systemic lupus erythematosis (SLE), autoimmune polyarthritis, pemphigus vulgaris and autoimmune thrombocytopenia. ANA Titer (level) can also be elevated in many chronic inflammatory and infectious diseases of dogs and cats that are not autoimmune in nature – diseases such as
ehrlichiosisbartonellosis and babesiosis.  A few cats and dogs have an increase in their ANA level without veterinarians ever discovering an underlying disease – particularly as they age. Converting to a positive ANA status can also occur post-vaccination. That is particularly true after receiving vaccines containing leptospirosis antigens or subsequent to a natural case of leptospirosis. (read here

The Diagnostic Laboratory of the University of Georgia Veterinary School puts little faith in the value of the ANA test in animals. Quoting their website: ” There is no consensus as to what is a significant ANA titer in animals. Many investigators feel that titers >10 are significant while others feel that titers > 40 are significant. A negative result does not rule out systemic lupus erythematous or other immune-mediated diseases as these conditions can occur without detectable antinuclear antibodies”. The one veterinarians are most familiar with is mucocutaneous junction disease. (read here)


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