Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Diagnostic yield of colonoscopy for melena after nondiagnostic upper endoscopy is lower than previously reported

A new study from researchers in Oregon reports that the diagnostic yield of colonoscopy to investigate melena after a nondiagnostic upper endoscopy is lower, 4.8 percent, than previously reported.

The rate of therapeutic intervention in this population is very low; therefore, patients with melena and a nondiagnostic upper endoscopy who are stable and without evidence of ongoing bleeding may be able to safely undergo elective colonoscopy.

This study is the largest to-date to examine the diagnostic yield of colonoscopy to investigate melena after a nondiagnostic upper endoscopy in patients from a broad geographic distribution and a variety of clinical practice settings. The study appears in the April issue of GIE: Gastrointestinal Endoscopy, the monthly peer-reviewed scientific journal of the American Society for Gastrointestinal Endoscopy (ASGE).

Melena is the passage of dark tarry stools containing decomposing blood that is usually an indication of bleeding in the upper part of the alimentary canal. The alimentary canal is a long tube made up of the esophagus, stomach, small intestine, and large intestine into which food is taken and digested and from which wastes are passed out of the body. Melena is most frequently caused by an upper gastrointestinal (GI) bleeding source, however, upper endoscopy can be nondiagnostic for a specific source of bleeding in approximately one-fourth of cases in this patient population. It is known that blood in the cecum (the beginning of the large intestine) can also result in melena, demonstrating that lower GI bleeding sources can cause melena. Consequently, colonoscopy is frequently performed in patients with melena after a nondiagnostic upper endoscopy in order to exclude a lower GI source of the melena.

Previous studies on the diagnostic yield of colonoscopy in patients with melena described a relatively high rate of finding sources of bleeding. These small studies found diagnostic yields of 23 percent to 35 percent for colonoscopy in this patient population.

"We performed this study to describe the diagnostic yield and rate of therapeutic intervention of colonoscopy in this patient population and compare the diagnostic yield with a control population of average-risk patients having screening colonoscopies. We hypothesized that the diagnostic yield of colonoscopy in this clinical setting is lower than previously described but higher than that of average-risk screening patients and that the rate of therapeutic intervention during colonoscopy in patients with melena and a nondiagnostic upper endoscopy is low," said study lead author Jason P. Etzel, MD, Oregon Health and Science University, Portland. "Our results showed an overall low rate, 4.8 percent, of locating a bleeding source on colonoscopy. In addition, the rate of therapeutic intervention during colonoscopy for bleeding was very low at 1.7 percent, suggesting that the majority of these procedures are diagnostic only and could be performed on an elective basis."


This was a retrospective case-control study that involved patients in the Clinical Outcomes Research Initiative (CORI) database with a colonoscopy performed to investigate melena within 30 days of a nondiagnostic upper endoscopy for the same indication. A control group had colonoscopies performed for average-risk screening. The CORI database is an endoscopic database that collects data from community, academic, and Veterans Affairs settings across a broad geographic area in the United States. Main outcome measurements were the endoscopic finding of a suspected bleeding source, defined as right-sided arteriovenous malformation, colitis, polyp ¡Ý 20 mm, tumor, or ulcer, as well as the rate of therapeutic intervention during colonoscopy.


A total of 1,743 colonoscopies were performed to evaluate melena after a nondiagnostic upper endoscopy for the same indication. The melena population included more individuals with advanced age, more men, higher American Society of Anesthesiologists (ASA) Physical Status Classification System scores, and more warfarin use than average-risk screening controls. Melena-related colonoscopies were more likely to be conducted on inpatients, have lower quality bowel preparation, and have fellow involvement than colonoscopies on controls. Colonoscopy was performed the same day as upper endoscopy in 59 percent of cases.

All of the anticipated sources of suspected bleeding were more prevalent in patients with melena, except for polyps ¡Ý 20 mm in the right side of the colon. The overall rate of finding a suspected lower GI bleeding source in patients with melena was 4.76 percent compared with 1.28 percent in the control population. Notably, colon tumors were nearly three times more likely in the patients with melena than the average risk screening control group. The overall rate of endoscopic therapy in the population with melena was low, with therapy being performed in 1.7 percent of melena-related colonoscopies.

The researchers concluded that the diagnostic yield of colonoscopy to investigate melena after a nondiagnostic upper endoscopy is lower than previously reported. Moreover, the rate of therapeutic intervention in this population is very low; therefore, patients with melena and a nondiagnostic upper endoscopy who are stable and without evidence of ongoing bleeding may be able to safely undergo elective colonoscopy. Colonoscopy remains useful in this group of patients as they are at increased risk of colorectal cancer. The decision on timing of colonoscopy must be made based on an assessment of the overall clinical context.

About the American Society for Gastrointestinal Endoscopy

Since its founding in 1941, the American Society for Gastrointestinal Endoscopy (ASGE) has been dedicated to advancing patient care and digestive health by promoting excellence in gastrointestinal endoscopy. ASGE, with more than 12,000 members worldwide, promotes the highest standards for endoscopic training and practice, fosters endoscopic research, recognizes distinguished contributions to endoscopy, and is the foremost resource for endoscopic education. Visit and for more information and to find a qualified doctor in your area.

About Endoscopy

Endoscopy is performed by specially-trained physicians called endoscopists using the most current technology to diagnose and treat diseases of the gastrointestinal tract. Using flexible, thin tubes called endoscopes, endoscopists are able to access the human digestive tract without incisions via natural orifices. Endoscopes are designed with high-intensity lighting and fitted with precision devices that allow viewing and treatment of the gastrointestinal system.

Anne Brownsey | EurekAlert!
Further information:

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>



Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

More VideoLinks >>>