Cross-sectional evaluation of online direct-to-public calprotectin testing

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Objective Why about a quarter of patients with inflammatory bowel disease (IBD) suffer symptoms for more than a year before their diagnosis made is unclear. Low public awareness, embarrassment and the apprehension of invasive tests are cited. The anonymity of direct-to-public calprotectin testing may overcome these barriers. We sought to characterise what calprotectin testing is available directly to the public in the UK. Design/method We conducted a cross-sectional evaluation of the calprotectin assays available online in the UK. Collection kits were procured from eligible providers, and surplus stool tested to receive follow-up advice for known positive (>50–100 μg/g) and negative (<50 μg/g) stool samples. Results Half (54.5% (6/11)) of the available tests were home lateral flow tests and the remainder were laboratory-based ELISAs. The lateral flow tests were considerably cheaper than the laboratory-based tests (median (range) cost £14.20 (£7.85–21.00) vs £75.85 (£59–151), p<0.0001). The median turnaround time for the laboratory tests was 14 (range: 1–23) days. All but one provider used a positivity threshold of 50 μg/g. All tests included written and pictorial instructions with the testing kit. Contact with a physician was recommended for similar proportions of positive and negative calprotectin results (54.5% (6/11) vs 54.5% (6/11), p=1). Conclusion In the UK, the public can choose between inexpensive home-based lateral flow tests or send stool samples for gold-standard laboratory testing of calprotectin. The low cost and rapid turnaround times suggest that direct-to-public calprotectin testing could be promoted to try to reduce the time to IBD diagnosis.