CRC screening: Smartphone-based stool test matches lab accuracy
The findings point to a new tool for enhancing participation in CRC screening programs—particularly among younger, tech-savvy patients under 60 years who demonstrated higher adoption rates.
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11/06/2025
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by Amy Pfeiffer
A smartphone-based fecal immunochemical test (FIT) was found to be a reliable and accessible tool for colorectal cancer (CRC) screening, according to the results of a new population-based study published in Clinical Gastroenterology and Hepatology. The mobile app–enabled FIT achieved diagnostic performance comparable to laboratory-based FITs while significantly improving patient convenience and participation.
"In this first study to evaluate the utilization and performance of a digital smartphone-based test for early detection of CRC at home, more than one-half of the participants made use of the test, with higher rates among male participants and the most important target group under age 60 years," reported Michael Hoffmeister, PhD, of the German Cancer Research Center in Heidelberg, and colleagues.
The researchers enrolled 654 patients who were scheduled for screening colonoscopy across gastroenterology practices in southern Germany between 2021 and 2023. Participants were offered both a smartphone-based FIT (SmarTest FIT) and a laboratory-based FIT (FOB Gold). Fifty-five percent of participants used the smartphone-based FIT, while 98% used the laboratory FIT. Of those who used the smartphone test, 76% had valid results. Overall, 89% of participants found the smartphone-based FIT a useful alternative to the standard test.
Of the 361 participants using the smartphone-based FIT, 24% (87 people) had a failed test—meaning they began the process but did not submit a result. Among those with failed tests, 32% did not own a smartphone, and 51% encountered issues during testing—most often believing they had completed it (34%).
The sensitivity for detecting advanced neoplasms was 28% for the smartphone-based FIT vs 34% for the laboratory FIT, with identical specificity at 92%. Receiver operating characteristic analysis showed nearly equivalent—though not statistically significant—diagnostic accuracy, which suggested that the smartphone-based approach performs on par with standard FITs under real-world conditions.
The smartphone-based FIT uses a rapid immunochemical test cassette that is analyzed through a smartphone app and quantifies hemoglobin concentration in stool via color intensity. Users collect a stool sample, apply it to the cassette, and scan the test after 15 minutes using their phone’s camera, reported Hoffmeister and colleagues.
A feasibility questionnaire revealed overwhelmingly positive patient feedback. Of the participants, 92% agreed the app offered clear guidance, 94% found stool handling manageable, 89% felt test duration was appropriate, and 78% supported immediate result display within the app. Common barriers among nonusers included technical issues (47%), such as app or smartphone compatibility, and general skepticism toward digital testing (44%).
The findings point to a new tool for enhancing participation in CRC screening programs—particularly among younger, tech-savvy patients under 60 years who demonstrated higher adoption rates, noted investigators. Although colonoscopy remains the diagnostic gold standard, smartphone-based FITs could bridge gaps in accessibility by enabling at-home testing and digital result transmission. A positive test result, however, must still be followed by colonoscopy and physician consultation, they emphasized.
Integrating digital self-tests could help increase participation rates in colorectal cancer screening overall, provided quality controls are maintained. Further research may focus on long-term adherence, impact on CRC detection rates, and cost-effectiveness within organized screening programs.
The researchers disclosed no conflicts of interest.
Summary content
7 Key Takeaways
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Developed a paper-based colorimetric sensor array for chemical threat detection.
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Can detect 12 chemical agents, including industrial toxins.
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Production cost is under 20 cents per chip.
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Utilizes dye-loaded silica particles on self-adhesive paper.
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Provides rapid, simultaneous identification through image analysis.
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Inspired by the mammalian olfactory system for pattern recognition.
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Future developments include a machine learning-enabled reader device.
The guidelines emphasize four-hour gastric emptying studies over two-hour testing. How do you see this affecting diagnostic workflows in practice?
Dr. Staller: Moving to a four-hour solid-meal scintigraphy will actually simplify decision-making. The two-hour reads miss a meaningful proportion of delayed emptying; standardizing on four hours reduces false negatives and the “maybe gastroparesis” purgatory that leads to repeat testing. Practically, it means closer coordination with nuclear medicine (longer slots, consistent standardized meal), updating order sets to default to a four-hour protocol, and educating front-line teams so patients arrive appropriately prepped. The payoff is fewer equivocal studies and more confident treatment plans.
Metoclopramide and erythromycin are the only agents conditionally recommended for initial therapy. How does this align with what is being currently prescribed?
Dr. Staller: This largely mirrors real-world practice. Metoclopramide remains the only FDA-approved prokinetic for gastroparesis, and short “pulsed” erythromycin courses are familiar to many of us—recognizing tachyphylaxis limits durability. Our recommendation is “conditional” because the underlying evidence is modest and patient responses are heterogeneous, but it formalizes what many clinicians already do: start with metoclopramide (lowest effective dose, limited duration, counsel on neurologic adverse effects) and reserve erythromycin for targeted use (exacerbations, bridging).
Several agents, including domperidone and prucalopride, received recommendations against first-line use. How will that influence discussions with patients who ask about these therapies?
Dr. Staller: Two points I share with patients: evidence and access/safety. For domperidone, the data quality is mixed, and US access is through an FDA IND mechanism; you’re committing patients to EKG monitoring and a non-trivial administrative lift. For prucalopride, the gastroparesis-specific evidence isn’t strong enough yet to justify first-line use. So, our stance is not “never,” it’s just “not first.” If someone fails or cannot tolerate initial therapy, we can revisit these options through shared decision-making, setting expectations about benefit, monitoring, and off-label use. The guideline language helps clinicians have a transparent, evidence-based conversation at the first visit.
The guidelines suggest reserving procedures like G-POEM and gastric electrical stimulation for refractory cases. In your practice, how do you decide when a patient is “refractory” to medical therapy?
Dr. Staller: I define “refractory” with three anchors.
1. Adequate trials of foundational care: dietary optimization and glycemic control; an antiemetic; and at least one prokinetic at appropriate dose/duration (with intolerance documented if stopped early).
2. Persistent, function-limiting symptoms: ongoing nausea/vomiting, weight loss, dehydration, ER visits/hospitalizations, or malnutrition despite the above—ideally tracked with a validated instrument (e.g., GCSI) plus nutritional metrics.
3. Objective correlation: delayed emptying on a standardized 4-hour solid-meal study that aligns with the clinical picture (and medications that slow emptying addressed).
At that point, referral to a center with procedural expertise for G-POEM or consideration of gastric electrical stimulation becomes appropriate, with multidisciplinary evaluation (GI, nutrition, psychology, and, when needed, surgery).
What role do you see dietary modification and glycemic control playing alongside pharmacologic therapy in light of these recommendations?
Dr. Staller: They’re the bedrock. A small-particle, lower-fat, calorie-dense diet—often leaning on nutrient-rich liquids—can meaningfully reduce symptom burden. Partnering with dietitians early pays dividends. For diabetes, tighter glycemic control can improve gastric emptying and symptoms; I explicitly review medications that can slow emptying (e.g., opioids; consider timing/necessity of GLP-1 receptor agonists) and encourage continuous glucose monitor-informed adjustments. Pharmacotherapy sits on top of those pillars; without them, medications will likely underperform.
The guideline notes “considerable unmet need” in gastroparesis treatment. Where do you think future therapies or research are most urgently needed?
Dr. Staller: I see three major areas.
1. Truly durable prokinetics: agents that improve emptying and symptoms over months, with better safety than legacy options (e.g., next-gen motilin/ghrelin agonists, better-studied 5-HT4 strategies).
2. Endotyping and biomarkers: we need to stop treating all gastroparesis as one disease. Clinical, physiologic, and microbiome/omic signatures that predict who benefits from which therapy (drug vs G-POEM vs GES) would transform care.
3. Patient-centered trials: larger, longer RCTs that prioritize validated symptom and quality-of-life outcomes, include nutritional endpoints, and reflect real-world medication confounders.
Our guideline intentionally highlights these gaps to hopefully catalyze better trials and smarter referral pathways.
Dr. Staller is with the Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston.