A positive ANA test does not mean a patient has cancer. Instead, the patient may have an autoimmune disease such as lupus, rheumatoid arthritis or scleroderma, explains Mayo Clinic.
The ANA test measures the level of antinuclear antibodies present in the blood, explains WebMD. Antibodies are produced by the body to fight infection, but antinuclear antibodies attack the body instead during what is known as an autoimmune reaction. Doctors use the result of the ANA test alongside present symptoms and a physical examination to arrive at a diagnosis. Some people can have positive ANA test results even if they are healthy, according to Mayo Clinic.