Nuclear Ab (immunofluorescence)

An ANA test is a blood test that looks for antinuclear antibodies in your blood. Antibodies are proteins that your immune system makes to fight foreign substances, like viruses and bacteria. But an antinuclear antibody attacks your healthy cells instead. It's called "antinuclear" because it targets the nucleus of the cells, which is in charge of sending signals that are needed for important cell functions.