High Ana? Antinuclear Antibodies

An ANA test detects antinuclear antibodies in your blood. Your immune system normally makes antibodies to help you fight infection. In contrast, antinuclear antibodies often attack your body's own tissues — specifically targeting each cell's nucleus.

In most cases, a positive ANA test indicates that your immune system has launched a misdirected attack on your own tissue — in other words, an autoimmune reaction. But some people have positive ANA tests even when they're healthy.


However, a level of 1:640 is pretty high. A homogenous (diffuse) pattern is usually associated with SLE and mixed connective tissue disease.

But, again, usually patients will have symptoms to go along with the positive ANA, or other lab tests will show signs of inflammation. The ESR and CRP test are very sensitive for any inflammatory processes going on. So, if a patient has an inflammatory process like SLE or one of the inflammatory arthropathies, their inflammatory markers should be elevated. However, one sign of inflammation is an elevated platelet count. It used to be said that the platelet count was the poor man’s ESR and CRP.

There are also a number of drugs and some infections (such as chronic non-viral hepatitis, primary biliary cirrhosis) that can give a false positive result for the ANA test.

A positive ANA can also mean that the person has drug-induced lupus. This condition is associated with the development of autoantibodies to histones, which are water-soluble proteins rich in the amino acids lysine and arginine. An anti-histone test may be ordered to support the diagnosis of drug-induced lupus. Some blood pressure medicines can cause this.


A doctor must rely on test results, clinical symptoms, and the person's history for diagnosis. Because symptoms may come and go, it may take months or years to show a pattern that might suggest SLE or any of the other autoimmune diseases.

So, even though you may not have symptoms yet, you may develop them down the road. If no other reason can be found, you should probably still be periodically evaluated for the later development of SLE.

Good luck.