In their recent article, Cummings and colleagues comment on the vast
differential diagnosis for Crohns disease (1). Coupling this with its
relatively low incidence, diagnosis of Crohns is often delayed. They
advise the primary care physician of tests that can be done in the
community to aid in making the diagnosis, such as the full blood count, C-
reactive protein (CRP) and stool culture.
Sub-classifying inflammatory bowel disease (IBD) into either Crohn’s,
ulcerative colitis (UC) or indeterminate colitis is sometimes challanging.
It is estimated that using the current diagnostic criteria, almost 10% of
patients will be misclassified (2).
Anti-Saccharomyces cerevisiae antibodies (ASCA) have been described
in patients with Crohn’s disease, whilst perinuclear anti-neutrophil
cytoplasmic antibodies (pANCA) have been detected in patients with
ulcerative colitis. Assays of these antibodies have been shown to be
effective in diagnosing and sub-classifying IBD.
Reese and colleagues (2) performed a meta-analysis of studies
reporting on ASCA and pANCA in IBD. They found the presence of either
pANCA or ASCA antibodies of any class was most sensitive for
differentiating between IBD and non-IBD (sensitivity 62.6%, specificity
92.6%). The ASCA positive with pANCA negative test offered the best
sensitivity (55%) and specificity (93%) for diagnosing Crohn’s disease.
For UC a positive pANCA test in the absence of information regarding ASCA
status had a sensitivity and specificity of 55% and 93% respectively.
ASCA and pANCA are specific but not sensitive for diagnosing Crohn’s
and UC. They can therefore play a key role when sub-classifying IBD.
References
1. Cummings JRF, Keshav S, Travis SPL. Medical management of Crohn’s
disease.
BMJ 2008; 336: 1062 - 1066.
2. Reese GE, Constantinides VA, Simillis C, et al. Diagnostic
Precision of Anti-Saccharomyces cerevisiae Antibodies and Perinuclear
Antineutrophil Cytoplasmic Antibodies in Inflammatory Bowel Disease. Am J
Gastroenterol 2006;101:2410–2422)
Competing interests:
None declared
Competing interests:
No competing interests
13 May 2008
Mohammed A Butt
ST2 general medicine
Mallick S F1 medicine, Ahammed SF F2 medicine, Donnelly A ST2 medicine
Rapid Response:
Antibodies in inflammatory bowel disease
In their recent article, Cummings and colleagues comment on the vast differential diagnosis for Crohns disease (1). Coupling this with its relatively low incidence, diagnosis of Crohns is often delayed. They advise the primary care physician of tests that can be done in the community to aid in making the diagnosis, such as the full blood count, C- reactive protein (CRP) and stool culture.
Sub-classifying inflammatory bowel disease (IBD) into either Crohn’s, ulcerative colitis (UC) or indeterminate colitis is sometimes challanging. It is estimated that using the current diagnostic criteria, almost 10% of patients will be misclassified (2).
Anti-Saccharomyces cerevisiae antibodies (ASCA) have been described in patients with Crohn’s disease, whilst perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) have been detected in patients with ulcerative colitis. Assays of these antibodies have been shown to be effective in diagnosing and sub-classifying IBD.
Reese and colleagues (2) performed a meta-analysis of studies reporting on ASCA and pANCA in IBD. They found the presence of either pANCA or ASCA antibodies of any class was most sensitive for differentiating between IBD and non-IBD (sensitivity 62.6%, specificity 92.6%). The ASCA positive with pANCA negative test offered the best sensitivity (55%) and specificity (93%) for diagnosing Crohn’s disease. For UC a positive pANCA test in the absence of information regarding ASCA status had a sensitivity and specificity of 55% and 93% respectively.
ASCA and pANCA are specific but not sensitive for diagnosing Crohn’s and UC. They can therefore play a key role when sub-classifying IBD.
References
1. Cummings JRF, Keshav S, Travis SPL. Medical management of Crohn’s disease. BMJ 2008; 336: 1062 - 1066.
2. Reese GE, Constantinides VA, Simillis C, et al. Diagnostic Precision of Anti-Saccharomyces cerevisiae Antibodies and Perinuclear Antineutrophil Cytoplasmic Antibodies in Inflammatory Bowel Disease. Am J Gastroenterol 2006;101:2410–2422)
Competing interests: None declared
Competing interests: No competing interests