Investigations

• blood count ^c  
• ESR ^c 
• CRP ^b  
• urea, electrolytes, creatinine ^d
• glucose ^d
• calcium, magnesium ^d
• liver function tests ^b
• group & save/ cross-match blood ^d
• ANCA and ASCA in new cases ^a
  
  
• stool culture and microscopy ^d
• C difficile toxin assay ^d
  
  
• erect chest X-ray ^d
• abdominal X-ray ^c 

• colonoscopy ^c  with biopsies. ^d It is a better test than sigmoidoscopy followed by barium enema. ^a  
• an air enema. ^b  
  Look for severe changes (irregular mucosal contour, > 2 mm deep ulceration, or ulceration undermining the mucosa).

• abdominal ultrasound scan ^b  
• white cell scanning ^c  

Barium follow-through studies are unhelpful ^c  

• vital signs ^c  
• number of stools passed per day ^{b  c}  
• blood count ^c  
• inflammatory markers ^{b  c}  
• urea and electrolytes ^d
• abdominal film for small bowel distension ^c