False-positive fecal immunochemical test results in colorectal cancer screening and gastrointestinal drug use

Alternative diagnoses and demographics associated with a raised quantitative faecal immunochemical test in symptomatic patients

“…Independent predictors of false positivity were younger age (OR, 1.28 (95% CI: 1.12–1.46; p = 0.0002)), female sex (OR, 2.31 (95% CI: 2.03–2.64; p < 0.0001)), successive screening round (OR, 1.53 (95% CI: 1.35–1.74; p < 0.0001)), aspirin (OR, 1.30 (95% CI: 1.04–1.64; p = 0.02)), NSAID (OR, 1.48 (95% CI: 1.23–1.78; p < 0.0001)), PPI (OR 1.39 (95% CI: 1.18–1.65; p = 0.0001)), antibiotics (OR, 1.32 (95% CI: 1.03–1.71; p = 0.03)) and laxative (OR, 2.26 (95% CI: 1.06–4.80; p = 0.03)) use. Further studies have related false positivity in screening participants to both older age 29 and younger age, 25 , 30 female 25 , 26 , 30 , 32 and male sex, 29 smoking, 29 high BMI, 29 successive screening, 25 , 26 the use of aspirin, 25 NSAIDs, 25 PPIs, 25 , 26 , 31 antibiotics 25 and laxatives, 25 non-advanced adenomas, 27 diverticular disease 27 and anal pathology including haemorrhoids and anal fissures. 26 , 27 , 29 De Klerk et al 28 performed a systematic review and meta-analysis of such studies and found younger age, female sex, NSAIDs, PPIs, anal fissures and peptic ulceration to be predictors of FIT false positivity in screener participants.…”

“…Indeed, there is evidence that FIT can be used as a marker of disease activity in ulcerative colitis [16][17][18][19][20] and colonic Crohn's 21 as an adjunct to faecal calprotectin. Additionally, higher FIT positivity in the context of bowel cancer screening has been independently associated with older age, male sex, deprivation, aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), oral anticoagulants, proton pump inhibitors (PPIs), antibiotics and smoking [22][23][24][25] and false positivity has been related to younger age, female sex, smoking, high BMI, successive screening, aspirin, NSAIDs, PPIs, antibiotics, laxatives, non-advanced adenomas, diverticular disease, haemorrhoids, anal fissures and peptic ulceration [25][26][27][28][29][30][31][32] .…”

“…Additionally, higher FIT positivity in the context of bowel cancer screening has been independently associated with older age, male sex, deprivation, aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), oral anticoagulants, proton pump inhibitors (PPIs), antibiotics and smoking, [22][23][24][25] and false positivity has been related to younger age, female sex, smoking, high BMI, successive screening, aspirin, NSAIDs, PPIs, antibiotics, laxatives, non-advanced adenomas, diverticular disease, haemorrhoids, anal fissures and peptic ulceration. [25][26][27][28][29][30][31][32] To date, no studies have examined demographics which independently predict a raised f-Hb in symptomatic patients and very few have explored non-cancer diagnoses which correlate with f-Hb. We aimed to establish demographics and alternative pathologies associated with a raised f-Hb in a cohort of symptomatic patients.…”

Faecal Haemoglobin Estimated by Faecal Immunochemical Tests—An Indicator of Systemic Inflammation with Real Clinical Potential

“…In contrast, another recent review suggested that aspirin, antiplatelet agents, and oral anti-coagulants significantly lowered the positive predictive value (PPV) of FIT for detecting advanced colorectal neoplasia (ACRN) and thus might increase the number of false positive FIT results [30]. Recent interest has been focused on f-Hb and the use of proton pump inhibitors (PPI) with the suggestion [31] that PPI could cause false positive FIT results, supporting earlier work [32,33]: however, this finding has been refuted [34]. The mechanism by which PPI resulted in an increase in the false positive rate was stated to be unknown, but the hypothesis presented in [31] was that, consistent with the finding that antibiotic therapy was also associated with false positive results, it could be inferred that gut dysbiosis induced by PPI could be the cause.…”

“…Recent interest has been focused on f-Hb and the use of proton pump inhibitors (PPI) with the suggestion [31] that PPI could cause false positive FIT results, supporting earlier work [32,33]: however, this finding has been refuted [34]. The mechanism by which PPI resulted in an increase in the false positive rate was stated to be unknown, but the hypothesis presented in [31] was that, consistent with the finding that antibiotic therapy was also associated with false positive results, it could be inferred that gut dysbiosis induced by PPI could be the cause. However, the new hypothesis advocated here below provides an alternative and possibly more attractive explanation.…”