Ive done two achr antibody tests that only show i have achr modulating antibodies present but its within the normal range. why would i have achr modulating antibodies present in my blood but its not positive?

Diagnostic testing results show a range of normal levels. If results are above the normal numbers, there might be confirmation of a clinical diagnosis which correlates with symptoms, and signs.

We all have low levels of antibodies that are reactive with our tissues and cells. These antibodies are useful in removing old and dying cells. Wish you good health!

You cannot make a definitive diagnosis if myesthenia gravis unless your level is over the normal limit. That being said, I think your neurologist, who took a thorough history & performed a neurological examination should advise you about your test results & whether there's any other testing or follow-up advisable in your case or whether you unequivocally do not have myesthenia gravis.