ANA test

An ANA test detects antinuclear antibodies (ANA) 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.

Your doctor may order an ANA test if he or she suspects you have an autoimmune disease such as lupus, rheumatoid arthritis or scleroderma.


Why it's done How you prepare What you can expect Results

Many rheumatic diseases have similar signs and symptoms — joint pain, fatigue and fever. While an ANA test can't confirm a specific diagnosis, it can rule out some diseases. And if the ANA test is positive, your blood can be tested for the presence of particular antinuclear antibodies, some of which are specific to certain diseases.

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