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 New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>



Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

More VideoLinks >>>