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Cedars-Sinai Researchers Determine Smartphone App Can Assess Stool Form as Well as Gastroenterologists and Better than IBS Patients

Artificial intelligence performs BSS assessments with higher sensitivity and specificity than human diagnosticians

In a recent study conducted by scientists at Cedars-Sinai Medical Center in Los Angeles, researchers evaluated a smartphone application (app) that uses artificial intelligence (AI) to assess and characterize digital images of stool samples. The app, it turns out, matched the accuracy of participating gastroenterologists and exceeded the accuracy of study patients’ self-reports of stool specimens, according to a news release.

Though smartphone apps are technically not clinical laboratory tools, anatomic pathologists and medical laboratory scientists (MLSs) may be interested to learn how health information technology (HIT), machine learning, and smartphone apps are being used to assess different aspects of individuals’ health, independent of trained healthcare professionals.

The issue that the Cedars Sinai researchers were investigating is the accuracy of patient self-reporting. Because poop can be more complicated than meets the eye, when asked to describe their bowel movements patients often find it difficult to be specific. Thus, use of a smartphone app that enables patients to accurately assess their stools in cases where watching the function of their digestive tract is relevant to their diagnoses and treatment would be a boon to precision medicine treatments of gastroenterology diseases.

The scientists published their findings in the American Journal of Gastroenterology, titled, “A Smartphone Application Using Artificial Intelligence Is Superior to Subject Self-Reporting when Assessing Stool Form.”

Mark Pimentel, MD

“This app takes out the guesswork by using AI—not patient input—to process the images (of bowel movements) taken by the smartphone,” said gastroenterologist Mark Pimentel, MD (above), Executive Director of Cedars-Sinai’s Medically Associated Science and Technology (MAST) program and principal investigator of the study, in a news release. “The mobile app produced more accurate and complete descriptions of constipation, diarrhea, and normal stools than a patient could, and was comparable to specimen evaluations by well-trained gastroenterologists in the study.” (Photo copyright: Cedars-Sinai.)

Pros and Cons of Bristol Stool Scale

In their paper, the scientists discussed the Bristol Stool Scale (BSS), a traditional diagnostic tool for identifying stool forms into seven categories. The seven types of stool are:

  • Type 1: Separate hard lumps, like nuts (difficult to pass).
  • Type 2: Sausage-shaped, but lumpy.
  • Type 3: Like a sausage, but with cracks on its surface.
  • Type 4: Like a sausage or snake, smooth and soft (average stool).
  • Type 5: Soft blobs with clear cut edges.
  • Type 6: Fluffy pieces with ragged edges, a mushy stool (diarrhea).
  • Type 7: Watery, no solid pieces, entirely liquid (diarrhea). 

In an industry guidance report on irritable bowel syndrome (IBS)and associated drugs for treatment, the US Food and Drug Administration (FDA) said the BSS is “an appropriate instrument for capturing stool consistency in IBS.”

But even with the BSS, things can get murky for patients. Inaccurate self-reporting of stool forms by people with IBS and diarrhea can make proper diagnoses difficult.

“The problem is that whenever you have a patient reporting an outcome measure, it becomes subjective rather than objective. This can impact the placebo effect,” gastroenterologist Mark Pimentel, MD, Executive Director of Cedars-Sinai’s Medically Associated Science and Technology (MAST) program and principal investigator of the study, told Healio.

Thus, according to the researchers, AI algorithms can help with diagnosis by systematically doing the assessments for the patients, News Medical reported.

30,000 Stool Images Train New App

To conduct their study, the Cedars-Sinai researchers tested an AI smartphone app developed by Dieta Health. According to Health IT Analytics, employing AI trained on 30,000 annotated stool images, the app characterizes digital images of bowel movements using five parameters:

  • BSS,
  • Consistency,
  • Edge fuzziness,
  • Fragmentation, and
  • Volume.

“The app used AI to train the software to detect the consistency of the stool in the toilet based on the five parameters of stool form, We then compared that with doctors who know what they are looking at,” Pimentel told Healio.

AI Assessments Comparable to Doctors, Better than Patients

According to Health IT Analytics, the researchers found that:

  • AI assessed the stool comparable to gastroenterologists’ assessments on BSS, consistency, fragmentation, and edge fuzziness scores.
  • AI and gastroenterologists had moderate-to-good agreement on volume.
  • AI outperformed study participant self-reports based on the BSS with 95% accuracy, compared to patients’ 89% accuracy.

Additionally, the AI outperformed humans in specificity and sensitivity as well:

  • Specificity (ability to correctly report a negative result) was 27% higher.
  • Sensitivity (ability to correctly report a positive result) was 23% higher.

“A novel smartphone application can determine BSS and other visual stool characteristics with high accuracy compared with the two expert gastroenterologists. Moreover, trained AI was superior to subject self-reporting of BSS. AI assessments could provide more objective outcome measures for stool characterization in gastroenterology,” the Cedars-Sinai researchers wrote in their paper.

“In addition to improving a physician’s ability to assess their patients’ digestive health, this app could be advantageous for clinical trials by reducing the variability of stool outcome measures,” said gastroenterologist Ali Rezaie, MD, study co-author and Medical Director of Cedars-Sinai’s GI Motility Program in the news release.

The researchers plan to seek FDA review of the mobile app.

Opportunity for Clinical Laboratories

Anatomic pathologists and clinical laboratory leaders may want to reach out to referring gastroenterologists to find out how they can help to better serve gastro patients. As the Cedars-Sinai study suggests, AI smartphone apps can perform BSS assessments as good as or better than humans and may be useful tools in the pursuit of precision medicine treatments for patient suffering from painful gastrointestinal disorders.

—Donna Marie Pocius

Related Information:

Smartphone Application Using Artificial Intelligence is Superior to Subject Self-Reporting When Assessing Stool Form

Study: App More Accurate than Patient Evaluation of Stool Samples

Industry Guidance Report: Irritable Bowel Syndrome—Clinical Evaluation of Drugs

Artificial Intelligence-based Smartphone App for Characterizing Stool Form

AI Mobile App Improves on “Subjective” Patient-Reported Stool Assessment in IBS

Artificial Intelligence App Outperforms Patient-Reported Stool Assessments

FDA Expands Approval of Gastric Emptying Breath Test for Gastroparesis to Include At-home Administration Under Virtual Supervision

It may not be a boom trend, but more non-invasive diagnostic tests are coming to market as clinical laboratory tests that use breath as the specimen

Here’s a development that reinforces two important trends in diagnostics: non-invasive clinical laboratory assays and patient-self testing. Recently, the FDA expanded the clearance of one diagnostic test to allow patients to collect their own breath specimen at home under the supervision of the test manufacturer’s telehealth team.

The C-Spirulina Gastric Emptying Breath Test (GEBT) breath test from Cairn Diagnostics initially received federal Food and Drug Administration (FDA) approval in 2015. At that time, the test was required to be administered “at a physician’s office, a laboratory collection center, or in a tertiary care setting,” according to a 2016 news release.

Recently, however, the FDA announced it has “expanded the approval of the company’s 13C-Spirulina Gastric Emptying Breath Test (GEBT) to now include ‘at home’ administration under virtual supervision of Cairn Diagnostics.”

Self-administration of at-home tests by patients guided virtually by healthcare professionals is a major advancement in telehealth. But will this virtual-healthcare method be popular with both patients and their physicians?

Clinical Laboratory Diagnostics and Telehealth

Spurring a far greater acceptance of telehealth among patients and healthcare providers is one of the many ways the COVID-19 pandemic has impacted healthcare.

“Telehealth, particularly during the COVID-19 pandemic, has emerged as a preferred option for healthcare providers,” noted Kerry Bush, President and COO of Cairn Diagnostics, in a 2021 news release

Cairn’s GEBT detects gastroparesis, a disease which, according to the NIH National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), affects 50 people in every 100,000. According to the CDC, it is also sometimes a complication of diabetes. Symptoms include nausea, heartburn, bloating, a feeling of fullness long after eating a meal, vomiting, belching, and pain in the upper abdomen, the NIDDK notes.

In people with gastroparesis—sometimes called “delayed gastric emptying”—muscles that normally move food from the stomach to the small intestine do not work as they should, and the food remains in the stomach for too long. The traditional diagnostic tool used to diagnose gastroparesis is scintigraphy. The patient consumes a meal that has radioactive material mixed in and the digestion process is observed using a nuclear medicine camera as the material is eliminated through the bowels.

Cairn Diagnostics’ C-Spirulina Gastric Emptying Breath Test

Cairn Diagnostics’ C-Spirulina Gastric Emptying Breath Test (above) recently received an expansion to its initial 2015 FDA approval that enables patients to self-administer the test at-home while being virtually guided by the company’s telehealth team. GEBTs are interpreted by CLIA-certified clinical laboratories and the results sent to patients’ doctors within 24-48 hours after testing. (Photo copyright: Cairn Diagnostics.)

Virtual Telehealth GEBT versus Scintigraphy

The telehealth process for Cairn Diagnostic’s Gastric Emptying Breath Test (GEBT) differs significantly from traditional scintigraphy testing. Once a physician prescribes the test, Cairn’s telehealth team contacts the patient to describe the virtual process. The team then ships the at-home test kit to the patient. To complete the testing, Cairn provides the patient with a web-based link to a secure audio/video platform.

During administration of the GEBT, a Cairn technician coaches the patient and supervises via video. Once the test is complete, the patient returns the breath samples to the CLIA-certified clinical laboratory by overnight courier. The test results are sent to the prescribing physician within 24-48 hours after the lab receives the samples.

Discovering New Uses for Breath as a Specimen for Clinical Laboratory Testing

For obvious reasons, patients prefer diagnostics that use specimens obtained noninvasively. GEBT is the latest in a growing list of diagnostic tests that use breath as a specimen.

For example, at Johns Hopkins clinicians employ breath testing to diagnose several conditions, including:

Each of these tests involves the patient consuming a particular substance, technicians capturing breath samples at certain intervals, and clinical laboratory personnel analyzing the samples to look for indicators of disease or intolerance.

New Types of Breath Tests

Breath samples are commonly used to diagnose gastrointestinal issues, but researchers also are seeking methods of using them to diagnose and monitor respiratory conditions as well.

In a recent study published in Nature Nanotechnology, scientists explored how breath can be used to monitor respiratory disease, noting that although breath contains numerous volatile metabolites, it is rarely used clinically because biomarkers have not been identified.

“Here we engineered breath biomarkers for respiratory disease by local delivery of protease-sensing nanoparticles to the lungs. The nanosensors shed volatile reporters upon cleavage by neutrophil elastase, an inflammation-associated protease with elevated activity in lung diseases such as bacterial infection and alpha-1 antitrypsin deficiency,” the researchers wrote.

Indeed, the search for new ways to use breath as a biological sample is being pursued by numerous groups and organizations. Owlstone Medical in the UK, for example, is developing breathalyzer tests for the detection of cancer as well as inflammatory and infectious disease.

“Exhaled breath is more than just air,” notes the company’s website. “It contains over 1,000 volatile organic compounds (VOCs) as well as microscopic aerosol particles, also known as respiratory droplets, originating from the lungs and airways.”

Analyzing breath allows for the:

  • investigation of biomarkers of disease,
  • patient stratification by phenotype,
  • detection and monitoring treatment response, and
  • measurement of exposure to harmful substances.

In fact, so many studies on using breath as a specimen have been conducted that in “Breath Biomarkers in Asthma: We’re Getting Answers, But What Are the Important Questions?” researchers Peter J. Sterk, PhD, Professor of Pulmonology at Amsterdam University Medical Centers, and immunity and respiratory medicine specialist Stephen J. Fowler, MD, FRCP, Professor of Respiratory Medicine at the University of Manchester in the UK suggested that systematic reviews are now feasible. They published their article in the European Respiratory Journal.

“Whilst we are still in this discovery stage it is time to refine our study designs so that we can make progress towards tailored clinical application,” they wrote. “Breathomics is perhaps at the ‘end of the beginning’ for asthma at least; it has a ‘sexy’ name, some promising and consistent findings, and the key questions are at least being recognized.”

Better for Patients, Clinicians, and Clinical Laboratories

Virtual telehealth tests, ordered by physicians, administered at home, and interpreted in CLIA-certified clinical laboratories, is a trend pathologists may want to watch carefully, along with the development of other tests that use human breath as the specimen. 

Less invasive, more personalized diagnostic tools that can be administered at home are better for patients. When those tools also provide detailed information, clinicians can make better decisions regarding care. Clinical laboratories that approach the use of at-home tests creatively, and which can accurately and quickly process these new types of tests, may have a market advantage and an opportunity to expand and grow.

Dava Stewart

Related Information:

Cairn Diagnostics Approved for At-Home Admin of Breath Test

Cairn Diagnostics Delivers Virtual Administration of Its Novel 13C-Spirulina Gastric Emptying Breath Test

Cairn Diagnostics Launches FDA-Approved Spirulina Gastric Emptying Breath Test for Gastroparesis

NIDDK: Definition and Facts for Gastroparesis

CDC: Diabetes and Digestion

Nuclear Medicine Gastric Emptying

Johns Hopkins: Gastroenterology and Hepatology

Nature: Engineering Synthetic Breath Biomarkers for Respiratory Disease

A Breathalyzer for Disease

Breath Biopsy—Biomarkers on Exhaled Breath

Breath Biomarkers in Asthma: We’re Getting Answers, But What Are the Important Questions?

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