Does a positive 21 hydroxylase antibody test mean addision's disease even if the acth stimulation test comes back normal?

No. Unlikely to be addison's with normal acth stim. Need further testing.
Addison's disease. Aca ( adrenal auto antibodies ) and 21 hydroxylase anti bodies can cause auto immune adrenalitis and auto immune addison disease . 21-hydroxylase anti bodies are markers of auto immune addison's disease either by itself or with other auto immune endocrine disorders. Normal acth test indicates functioning adrenal cortex despite 21 hydroxylase anti bodies .