Common Question
My doctor told me my ANA test is positive but is not sure I have lupus. How can this be?
The body’s immune system normally produces antibodies that are designed to fight off diseases and infections. In an autoimmune disease, something goes wrong with this system and the person’s body begins producing antibodies against their own tissues. Antinuclear antibodies (ANA) are antibodies that react with the cell nucleus (the central controlling part of the cell).
The ANA test looks at the concentration of antinuclear antibodies in a person’s blood. A positive result means that you have a higher than “normal” concentration of these antibodies. The incidence of a positive ANA in normal people increases with age, and for example, it is quite common to find weak positive ANA in the elderly population, in whom lupus is rare.
ANA testing is one of the tools in diagnosing lupus as well as several other autoimmune diseases, so a positive result may be related to lupus or another disease. Just having an ANA does not equate to a diagnosis of lupus. You may simply have a higher than normal concentration of these antibodies just as some people’s normal body temperature is higher or lower than 98.6°. To make a diagnosis of lupus, there should be suggestive clinical features, and often other abnormal laboratory results.
Even among people with lupus, the ANA results can vary widely – one person can be in remission at a certain level of ANA while another can be extremely ill at the same level. Interpreting what these results mean for you is the work of your doctor.
For more FAQs, see the ‘Lupus A to Z: Q & A Overview’ pages on the Lupus UK website.
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