Anti–Saccharomyces cerevisiae IgA antibodies  have been proposed as a serologic method for differentiating Crohn disease from ulcerative colitis, but they are neither adequately sensitive nor specific and can lead to false-positive results if used as part of the initial assessment for gastrointestinal symptoms. have been proposed as a serologic method for differentiating Crohn disease from ulcerative colitis, but they are neither adequately sensitive nor specific and can lead to false-positive results if used as part of the initial assessment for gastrointestinal symptoms.

from ACP MKSAP