From the Guidelines
The sensitivity of anti-Saccharomyces cerevisiae antibodies for ulcerative colitis (UC) is limited, and their routine use for diagnosis is not clinically justified. The current evidence suggests that perinuclear anti-neutrophil cytoplasmic antibodies (pANCAs) are detected in up to 65% of patients with UC, whereas anti-Saccharomyces cerevisiae antibodies (ASCAs) have a lower sensitivity 1.
Key Points
- The sensitivity of ASCAs for UC is not explicitly stated in the provided evidence, but it is mentioned that their routine use for diagnosis is not justified due to limited sensitivity 1.
- pANCAs are more sensitive for UC, detected in up to 65% of patients, compared to ASCAs 1.
- Faecal calprotectin appears to be a more sensitive marker of intestinal inflammation in IBD, correlating well with endoscopic indices and useful in selecting patients for diagnostic investigation and assessing disease severity 1.
Clinical Implications
- ASCAs should not be used alone for the diagnosis of UC due to their limited sensitivity.
- A combination of serological markers, including pANCA, may improve diagnostic accuracy for UC.
- Faecal calprotectin is a useful non-invasive marker for monitoring UC patients and assessing disease severity.
From the Research
Sensitivity and Specificity of Anti-Saccharomyces Antibodies for UC
- The sensitivity and specificity of anti-Saccharomyces cerevisiae antibodies (ASCA) for ulcerative colitis (UC) are not directly addressed in the provided studies, as they primarily focus on the diagnostic value of ASCA in distinguishing Crohn's disease (CD) from UC 2, 3, 4, 5.
- However, the studies suggest that ASCA are more specific for CD than UC, with sensitivity and specificity values for CD ranging from 46% to 54.6% and 92.8% to 98.1%, respectively 2, 3, 4.
- In contrast, perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) are more specific for UC, with sensitivity and specificity values ranging from 39.6% to 55.3% and 88.5% to 92.5%, respectively 3, 4.
- The combined use of ASCA and pANCA may improve the diagnostic accuracy for UC, with one study reporting a correct diagnosis in 97% of UC patients 5.
- It is essential to note that the sensitivity and specificity of ASCA for UC are not explicitly stated in the provided studies, and more research is needed to determine their diagnostic value for UC specifically.