01.Here is another positive ANA in which the substrate cells are a human cell line known as Hep2. Any positive ANA is reported with a titer. The titer is simply the dilution of patient serum at which the test is still positive. The test has to be positive at greater than 1:16 or 1:20 (depending upon the lab) to be positive at all. In general, the higher the titer, the more likely a serious autoimmune disease is present. Thus, a 1:40 result might not mean much, but a 1:1012 certainly should not be ignored.