• Goodhand, J. R.
• Ahmad, T.
• Smith, Rebecca
• Bishara, M.
• Kennedy, N. A.
• Roberts, C.
• Nice, R.

Abstract

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>The longest component of the time-to-diagnosis is the interval between symptom onset and an individual seeking help. Recent reports in patients with sexually transmitted infections and hepatitis C, who also suffer health related stigma and a delay in diagnosis, suggest that this barrier may be overcome by the anonymity of direct-to-public testing. We sought to characterise the availability of online direct-to-public calprotectin testing in 2023 in the UK.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We undertook an online search using the Google search engine on May 25th, 2023, with the terms "buy" or "purchase" AND "calprotectin" AND "inflammatory bowel disease". Collection kits were procured, and stool samples tested to receive follow-up advice for known positive and negative stool samples. We recorded data regarding the assay, consumer information and the clinical advice offered on return of a positive and negative test.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Overall, 54.5% (6/11) of available tests were home lateral flow tests, the remainder were home collection laboratory-based tests. Of the laboratory-based tests, three were conventional enzyme-linked immunosorbent assay (ELISA) assays and two were OC sensor tests. The lateral flow tests were considerably cheaper than the laboratory-based tests (median cost £14.20 [£7.85-21.00] vs £75.85 [£59-151], p&amp;lt;0.0001). The median turnaround time for the laboratory tests was 14 (1-23) days. All but one provider used a positivity threshold of 50ug/g. Eight of the eleven platforms (4 lateral flow tests and 4 laboratory-based tests) explicitly stipulated testing in the setting of gastrointestinal symptoms or suggested exclusion criteria. All tests included written and pictorial instructions with the testing kit. The median Flesch Kincaid readability score for the instructions and result reporting were 54.3 (43.9-73.7) and 51.8 (12.9-64.9): equivalent to a school reading grade of 9.2 (6.2-10.8) and 11.3 (7.2-15.8), respectively. Only two of the lateral flow tests provided written recommendations about follow up of positive results, whereas amongst the laboratory-based tests, all but one provider recommended onward discussion with a general practitioner or specialist. Two providers offered private referrals or consultations and six provided safety netting advice with regards to negative results.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>In the UK online direct-to-public calprotectin testing is already readily available from multiple providers. Consumers can choose between home-based lateral flow tests or conventional laboratory testing. Further work is needed to redefine the diagnostic accuracy of calprotectin used in this way, however, the rapid turnaround times and anonymity suggest that direct-to-public calprotectin testing could be used to reduce the time to IBD diagnosis.</jats:p></jats:sec>

Topics

• impedance spectroscopy
• size-exclusion chromatography