Antinuclear antibody 1:100 is the lowest titer of weak positivity and can be positive in many normal people, especially in the elderly. Antinuclear antibodies are autoantibodies that are positive for connective tissue diseases, including systemic lupus erythematosus, desiccation syndrome, and mixed connective tissue diseases. 1:100 is a weak positive at the lowest titer, and many normal people can be positive, especially the elderly, so it is not possible to draw conclusions from only having antinuclear antibodies that are positive at 1:100. Depending on whether there are clinical signs associated with connective tissue disease, such as fever, fatigue, joint and muscle pain, rash, Raynaud’s phenomenon, etc., the patient may be able to further examine the full antinuclear antibody panel to see if there are specific antibodies. It is recommended that patients with 1:100 antinuclear antibody test should go to the hospital in time to avoid delaying their condition.