Inflammatory bowel disease: a systematic review on the value of diagnostic testing in primary care

Aim The clinical presentation of inflammatory bowel disease in primary care represents a diagnostic challenge as its symptoms are heterogeneous and common. To assist the primary care physician, we have summarized the available evidence on diagnostic tests in patients with abdominal symptoms. Method We searched PubMed and Embase and screened references. Studies were selected if the design was a primary diagnostic study. Patients were adults attending with nonacute abdominal symptoms. Tests included clinical assessment, blood or faecal tests or abdominal ultrasonography. Quality assessment using a modified version of the QUADAS tool and data extraction was performed by two reviewers independently. Diagnostic two-by-two tables and pooled estimates of sensitivity and specificity are given. We refrained from pooling when there was considerable clinical or statistical heterogeneity. Results A total of 24 studies were included. While the diagnostic performance of the individual symptoms was highly variable (range sensitivity 0.0-0.96, specificity 0.09-1.0), the performance of symptom-based classification systems was both more consistent and better (sensitivity 0.65-1.0, specificity 0.17-0.82). Among faecal and blood tests, calprotectin was studied most frequently and showed the best results (sensitivity 0.61-1.0, specificity 0.71-1.0). Statistical pooling for ultrasonography resulted in a sensitivity of 0.73 (0.65-0.80) and a specificity of 0.95 (0.91-0.97). Conclusion Although calprotectin and ultrasonography showed consistent and promising findings, none of the studies was performed in primary care. To assist primary care physicians in diagnostic decision making, we urgently need high quality studies performed in primary care.