Do you mean "non-reactive"? Or possibly "indeterminate"?
A non reactive result is a negative result, and an indeterminate is really neither, it means more testing is needed.
It isn't uncommon to get a false POS which is sounds like what she had. The follow up test (most likely a "Western Blot") most likely will give a conclusive result.
I'm sure everything will be fine. Some people react to the one protein band for some reason....so her "Elisa" (usually the initial HIV test) would most likely ALWAYS come back positive, or indeterminate.
The test was coded as "non-diagnostic." If it said any of the other options (non-reactive, indeterminate, inconclusive, etc) I think it would be much less confusing.
She had a shingles and hepatitis vaccine prior to testing, so perhaps this caused some weird reaction with the test. She is obviously freaking, but my rational mind believes she is fine.