The presence of anti-Saccharamyces cerevisae antibody is a surrogate marker of one of the following-

Anti-Saccharomyces cerevisiae antibodies (ASCA) are immune proteins that are frequently present in people who have inflammatory bowel disease (IBD).Investigations are necessary to confirm the diagnosis, define disease distribution and activity, and identify complications. Full blood count may show anaemia resulting from bleeding or malabsorption of iron, folic acid or vitamin B12. Platelet count can also be high as a marker of chronic inflammation. Serum albumin concentration falls as a consequence of protein-losing enteropathy, inflammatory disease or poor nutrition. ESR andCRP are elevated in exacerbations and in response to abscess formation. Faecal calprotectin has a high sensitivity for detecting gastrointestinal inflammation and may be elevated, even when the CRP is normal. It is paicularly useful for distinguishing inflammatory bowel disease from irritable bowel syndrome at diagnosis, and for subsequent monitoring of disease activity. Ref Davidson edition23rd pg818