Hiya, I am giving this information as a person with SLE, not as a doctor.
The value of the ana test is determined by lots of factors. The results of an ANA test are usually given in titres, which is a measure of how much the blood sample can be diluted before the presence of the antibodies can no longer be detected.
For example, a titer of 1 to 40 (1:40) means that antibodies can be detected when 1 part of the blood sample is diluted by up to 40 parts of a salt solution (saline). A larger second number means there are more antibodies in the blood. Therefore, a titer of 1 to 80 indicates more antibodies in the blood than a titer of 1 to 40.
Some information states that a normal titre of 1:40 or less is normal, whilst other information states that a titre of 1:80 or lower is usually considered negative. Also results can vary from lab to lab.
It is always best to discuss the results with your rheumatologist/doctor.
Hope this helps you.
Take care - goldenwings