Discriminating IBD from IBS: comparison of the test performance of fecal markers, blood leukocytes, CRP, and IBD antibodies

Inflamm Bowel Dis. 2008 Jan;14(1):32-9. doi: 10.1002/ibd.20275.


Background: Symptoms of inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) can overlap. We aimed to determine the accuracy of fecal markers, C-reactive protein (CRP), blood leukocytes, and antibody panels for discriminating IBD from IBS and to define a "best test."

Methods: We prospectively included 64 patients with IBD (36 Crohn's disease [CD], 28 ulcerative colitis [UC]), 30 with IBS, and 42 healthy controls. Besides CRP and blood leukocytes, blinded fecal samples were measured for calprotectin (PhiCal Test, enzyme-linked immunosorbent assay [ELISA]), lactoferrin (IBD-SCAN, ELISA), Hexagon-OBTI (immunochromatographic test for detection of human hemoglobin), and LEUKO-TEST (lactoferrin latex-agglutination test). Blinded serum samples were measured for the antibodies ASCA (ELISA) and pANCA (immunofluorescence).

Results: Overall accuracy of tests for discriminating IBD from IBS: IBD-SCAN 90%, PhiCal Test 89%, LEUKO-TEST 78%, Hexagon-OBTI 74%, CRP 73%, blood leukocytes 63%, CD antibodies (ASCA+/pANCA- or ASCA+/pANCA+) 55%, UC antibodies (pANCA+/ASCA-) 49%. ASCA and pANCA had an accuracy of 78% for detecting CD and 75% for detecting UC, respectively. The overall accuracy of IBD-SCAN and PhiCal Test combined with ASCA/pANCA for discriminating IBD from IBS was 92% and 91%, respectively.

Conclusions: The PhiCal Test and IBD-SCAN are highly accurate for discriminating IBD from IBS. There is only marginal additional diagnostic accuracy when the PhiCal Test and IBD-SCAN are combined with ASCA and pANCA. ASCA and pANCA have a high specificity for IBD.

MeSH terms

  • Adult
  • Aged
  • Antibodies, Fungal / blood
  • C-Reactive Protein / analysis
  • Carrier Proteins / analysis
  • Diagnosis, Differential
  • Feces / chemistry
  • Female
  • Hemoglobins / analysis
  • Humans
  • Inflammatory Bowel Diseases / diagnosis*
  • Irritable Bowel Syndrome / diagnosis*
  • Lactoferrin
  • Leukocyte Count
  • Leukocyte L1 Antigen Complex / analysis
  • Male
  • Middle Aged
  • Prospective Studies
  • Sensitivity and Specificity


  • Antibodies, Fungal
  • Carrier Proteins
  • Hemoglobins
  • LTF protein, human
  • Leukocyte L1 Antigen Complex
  • C-Reactive Protein
  • Lactoferrin