Editing Crohn's disease (section)

=== Blood tests ===
A [[complete blood count]] may reveal anemia, which commonly is caused by blood loss leading to iron deficiency or by [[Cyanocobalamin|vitamin B{{ssub|12}}]] deficiency, usually caused by ileal disease impairing vitamin B{{ssub|12}} absorption. Rarely autoimmune hemolysis may occur.<ref>{{cite journal | vauthors = Goh J, O'Morain CA | title = Review article: nutrition and adult inflammatory bowel disease | journal = Alimentary Pharmacology & Therapeutics | volume = 17 | issue = 3 | pages = 307–320 | date = February 2003 | pmid = 12562443 | doi = 10.1046/j.1365-2036.2003.01482.x | s2cid = 72099458 | doi-access = free | title-link = doi }}</ref> [[Ferritin]] levels help assess if iron deficiency is contributing to the anemia. [[Erythrocyte sedimentation rate]] (ESR) and [[C-reactive protein]] help assess the degree of inflammation, which is important as ferritin can also be raised in inflammation.<ref>{{cite journal | vauthors = Chamouard P, Richert Z, Meyer N, Rahmi G, Baumann R | title = Diagnostic value of C-reactive protein for predicting activity level of Crohn's disease | journal = Clinical Gastroenterology and Hepatology | volume = 4 | issue = 7 | pages = 882–887 | date = July 2006 | pmid = 16630759 | doi = 10.1016/j.cgh.2006.02.003 }}</ref>

Other causes of anemia include medication used in the treatment of inflammatory bowel disease, like azathioprine, which can lead to cytopenia, and sulfasalazine, which can also result in [[folate deficiency]]. Testing for ''[[Saccharomyces cerevisiae]]'' antibodies (ASCA) and [[anti-neutrophil cytoplasmic antibody|antineutrophil cytoplasmic antibodies]] (ANCA) has been evaluated to identify inflammatory diseases of the intestine<ref>{{cite journal | vauthors = Kaila B, Orr K, Bernstein CN | title = The anti-Saccharomyces cerevisiae antibody assay in a province-wide practice: accurate in identifying cases of Crohn's disease and predicting inflammatory disease | journal = Canadian Journal of Gastroenterology | volume = 19 | issue = 12 | pages = 717–721 | date = December 2005 | pmid = 16341311 | doi = 10.1155/2005/147681 | doi-access = free | title-link = doi }}</ref> and to differentiate Crohn's disease from ulcerative colitis.<ref>{{cite journal | vauthors = Israeli E, Grotto I, Gilburd B, Balicer RD, Goldin E, Wiik A, Shoenfeld Y | title = Anti-Saccharomyces cerevisiae and antineutrophil cytoplasmic antibodies as predictors of inflammatory bowel disease | journal = Gut | volume = 54 | issue = 9 | pages = 1232–1236 | date = September 2005 | pmid = 16099791 | pmc = 1774672 | doi = 10.1136/gut.2004.060228 }}</ref> Furthermore, increasing amounts and levels of serological antibodies such as ASCA, antilaminaribioside [Glc(β1,3)Glb(β); ALCA], antichitobioside [GlcNAc(β1,4)GlcNAc(β); ACCA], antimannobioside [Man(α1,3)Man(α)AMCA], antiLaminarin [(Glc(β1,3))3n(Glc(β1,6))n; anti-L] and antichitin [GlcNAc(β1,4)n; anti-C] associate with disease behavior and surgery, and may aid in the prognosis of Crohn's disease.<ref>{{cite journal | vauthors = Ferrante M, Henckaerts L, Joossens M, Pierik M, Joossens S, Dotan N, Norman GL, Altstock RT, Van Steen K, Rutgeerts P, Van Assche G, Vermeire S | title = New serological markers in inflammatory bowel disease are associated with complicated disease behaviour | journal = Gut | volume = 56 | issue = 10 | pages = 1394–1403 | date = October 2007 | pmid = 17456509 | pmc = 2000264 | doi = 10.1136/gut.2006.108043 | first12 = S }}</ref><ref>{{cite journal | vauthors = Papp M, Altorjay I, Dotan N, Palatka K, Foldi I, Tumpek J, Sipka S, Udvardy M, Dinya T, Lakatos L, Kovacs A, Molnar T, Tulassay Z, Miheller P, Norman GL, Szamosi T, Papp J, Lakatos PL | title = New serological markers for inflammatory bowel disease are associated with earlier age at onset, complicated disease behavior, risk for surgery, and NOD2/CARD15 genotype in a Hungarian IBD cohort | journal = The American Journal of Gastroenterology | volume = 103 | issue = 3 | pages = 665–681 | date = March 2008 | pmid = 18047543 | doi = 10.1111/j.1572-0241.2007.01652.x | s2cid = 6015339 }}</ref><ref>{{cite journal | vauthors = Seow CH, Stempak JM, Xu W, Lan H, Griffiths AM, Greenberg GR, Steinhart AH, Dotan N, Silverberg MS | title = Novel anti-glycan antibodies related to inflammatory bowel disease diagnosis and phenotype | journal = The American Journal of Gastroenterology | volume = 104 | issue = 6 | pages = 1426–1434 | date = June 2009 | pmid = 19491856 | doi = 10.1038/ajg.2009.79 | s2cid = 25021606 }}</ref><ref>{{cite journal | vauthors = Dotan I | title = Serologic markers in inflammatory bowel disease: tools for better diagnosis and disease stratification | journal = Expert Review of Gastroenterology & Hepatology | volume = 1 | issue = 2 | pages = 265–274 | date = December 2007 | pmid = 19072419 | doi = 10.1586/17474124.1.2.265 | s2cid = 32035337 }}</ref>

Low serum levels of vitamin D are associated with Crohn's disease.<ref name="IBD2015">{{cite journal | vauthors = Del Pinto R, Pietropaoli D, Chandar AK, Ferri C, Cominelli F | title = Association Between Inflammatory Bowel Disease and Vitamin D Deficiency: A Systematic Review and Meta-analysis | journal = Inflammatory Bowel Diseases | volume = 21 | issue = 11 | pages = 2708–2717 | date = November 2015 | pmid = 26348447 | pmc = 4615394 | doi = 10.1097/MIB.0000000000000546 }}</ref> Further studies are required to determine the significance of this association.<ref name="IBD2015" />