investigations

Last reviewed 01/2018

• FBC - anaemia due to blood loss; leukocytosis
  
  
• ESR - increased; correlates with active disease
  
  
• CRP - raised; but less so than in Crohn's disease
  
  
• biochemistry - in active disease, biochemical abnormalities may include hypokalaemia, hyponatraemia, hypomagnesaemia, hypocalcaemia, and hyoalbuminaemia. Abnormal LFTs due to associated chronic active hepatitis - increased ALT - or sclerosing cholangitis - increased alkaline phosphatase
  
  
• ANCA - found in HLA-DR2 associated form of ulcerative colitis

• radiology:
• plain abdominal x-ray - excludes toxic dilatation, which is more than 5.5 cm in diameter in adults
• barium enema:
• diagnosis of extent and severity of the disease
• procedure is contraindicated in those patients at risk of a toxic dilatation

• rectal biopsy - taken at sigmoidoscopy
  
  
• colonoscopy - this is contraindicated in those patients at risk of toxic dilatation. Allows multiple biopsies to be taken throughout the colon and delineation of the extent and activity of the disease

• white cell scan - allows imaging in severe disease

• molecular biology - a high intensity of CD44v6 and v3 epitope expression on crypt epithelial cells in patients with UC has been noted. This observation may have diagnostic potential in distinguishing UC from Crohn's