On my ANA screen for lupus, what does 120 high mean?

ANA titers are elevated in many rheumatic disorders, such as systemic lupus erythematosus, juvenile rheumatoid arthritis, mixed connective disease, and Sj枚gren鈥檚 syndrome.

Lupus has many symptoms. Some common ones are:
Joint pain or swelling
Muscle pain
Fever with no known cause
Red rashes, often on the face (also called the "butterfly rash")

There is no one test to diagnose lupus, and it may take months or years to make the diagnosis. There is no cure for lupus, but medicines and lifestyle changes can help control it.

Was your ANA screen 1:120 maybe? A titer above 1:80 is usually considered positive. However, some laboratories may interpret different titer levels as positive, so one cannot compare titers from different laboratories.

A Positive ANA Does Not Equate to Having a Disease
The ANA should be looked at as a screening test. If it is positive in a person who is not feeling well and who has other symptoms or signs of lupus, the physician will probably want to conduct further tests for lupus. If the ANA is positive in a person who is feeling well and in whom there are no other signs of lupus, it can be ignored. If there is any doubt, a consultation with a rheumatologist should clarify the situation.
http://www.lupus.org/webmodules/webartic...

This is the best information I can find on an ANA screen test for lupus and/or related diseases. Symptoms also play a big role in diagnosis.

ANA stands for antinuclear antibodies. This means that you make antibodies against either the nucleii of healthy cells or the cell debris that enters the blood stream after a cell dies a normal death (apoptosis).

A positive ANA can be caused by many things, even pregnancy, and lupus is just one possibility.

A lupus patient's ANA can vary with disease activity. 5% of lupus patients will even have a negative ANA.

However, your ANA (assuming it is the ratio number) is not dreadfully high. But no matter what the cause, you need to establish good and open communication with your doctor. If the doctor will not answer, then get one who will.