 Rarely, however, a false positive heterophile antibody test may result from systemic lupus erythematosus, toxoplasmosis, rubella, lymphoma and leukemia.However, the sensitivity is only moderate, so a negative test does not exclude EBV.This lack of sensitivity is especially the case in young children, many of whom will not produce the heterophile antibody at any stage and thus have a false negative test result.