i am assuming by negative tests you mean negative pregnancy tests? it is possible for a woman to have discharge from her nipples even if she is not pregnant. this can be a sign of certain hormones being off balance. if it continues or worsens becomes painful or overly irritated it's time to see your doctor. they will more than likely do bloodwork to check certain horomones.
can a woman lactate without being pregnant? ive started lactating but ive had sevral (-) test results