Duodenal biopsy: indications, procedure and interpretation

A duodenal biopsy is the removal of small samples of mucosal tissue from the first section of the small intestine during a gastroscopy. The procedure is not intended to "look at the intestines with the naked eye," but rather to confirm or rule out disease under a microscope when an endoscopic examination alone is insufficient. [1]

In practice, the most common scenario remains the suspicion of celiac disease. The US National Institute of Diabetes and Digestive and Kidney Diseases clearly states: if serological tests suggest celiac disease, the next step should be gastroscopy with biopsies from the duodenum, including the bulb and distal portion. [2]

But celiac disease is not the only cause. A biopsy may be taken during gastroscopy to determine the cause of persistent upper gastrointestinal complaints, chronic diarrhea, signs of malabsorption, iron deficiency, or suspicious mucosal changes noted during examination. The British Society of Gastroenterology's position also emphasizes that duodenal biopsies are indicated when investigating iron deficiency anemia if serology for celiac disease is positive or has not been performed previously. [3]

A particular value of this method is that the mucosa may appear completely normal externally, but microscopically it already shows significant changes. This is especially important for diagnosing celiac disease, as the absence of obvious endoscopic signs does not rule out the disease. This is why modern standards emphasize not only examination but also the proper collection of a sufficient number of samples. [4]

Finally, a duodenal biopsy is a way not only to confirm a suspected diagnosis but also to detect other causes of symptoms. The NIDDK specifically notes that if serology is negative and the suspicion for celiac disease is still high, a biopsy may help identify either a seronegative form of celiac disease or another cause of the symptoms. [5]

What does a biopsy provide?	Practical benefits
Confirmation of diagnosis	Allows you to see changes in the mucous membrane under a microscope
Clarifying the cause of symptoms	Helps with chronic diarrhea, malabsorption, anemia
Diagnosis of celiac disease	Remains a key method in adults
Checking suspicious areas	Allows you to evaluate the altered mucous membrane not only visually
Exclusion of alternative causes	Important when serology and symptoms do not match

The table summarizes the clinical role of duodenal biopsy from the NIDDK, NHS, and British Society of Gastroenterology.[6]

When does a doctor usually order this test?

The most common reason for referral is positive tests for celiac disease. NICE recommends referring adolescents and adults with positive serological tests to a gastroenterologist for an endoscopic intestinal biopsy to confirm or exclude the diagnosis. This makes biopsy a standard part of the adult workup rather than a random option. [7]

Sometimes a biopsy is ordered even with negative serology if the symptoms and clinical picture are still concerning. The NIDDK states that a small percentage of patients with celiac disease may have negative serology, and in such cases, a biopsy helps detect the disease or other mucosal pathology. [8]

A separate category of indications relates to iron deficiency anemia and malabsorption. British quality standards for upper endoscopy specifically stipulate that duodenal samples are required when assessing iron deficiency anemia if celiac serology is positive or has not yet been measured. This is important for clinical practice, as anemia may be the only manifestation of celiac disease. [9]

A biopsy may also be performed if eosinophilic inflammatory disease of the upper gastrointestinal tract is suspected. Joint guidelines from the European Society of Pediatric Gastroenterology, Hepatology, and Nutrition and the North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition recommend that multiple biopsies, including the duodenum, are needed if eosinophilic gastritis or duodenitis is suspected. This is a more specific indication, but clinically feasible. [10]

Finally, tissue sampling is also possible for visible suspicious changes—nodules, ulcers, polyps, or atypical mucosal folding. According to the NIDDK, upper endoscopy is used to identify the causes of pain, vomiting, and swallowing difficulties, as well as to detect diseases, including celiac disease and malignancies. Therefore, a biopsy is a natural continuation of the examination if the physician sees an area that requires morphological confirmation. [11]

When biopsy is especially considered	Why
Positive serology for celiac disease	Morphological confirmation is required in adults.
Negative serology with high suspicion	Seronegative celiac disease or another cause must be excluded.
Iron deficiency anemia	Latent malabsorption is possible
Suspected eosinophilic inflammation	Tissue verification is required
Suspicious changes during gastroscopy	Examination is not enough, histology is needed

The table is based on recommendations from NICE, NIDDK, the British Society of Gastroenterology and ESPGHAN NASPGHAN.[12]

How to prepare and how the procedure goes

A duodenal biopsy is not performed separately, but rather during a gastroscopy, also known as an esophagogastroduodenoscopy. The NIDDK and NHS describe it as a test in which a long, thin, flexible endoscope is passed through the mouth into the esophagus, stomach, and duodenum. [13]

Preparation involves three key steps: discussing any medical conditions and medications with your doctor, arranging your transportation home in advance if sedation is planned, and not eating or drinking before the procedure. The NIDDK states that patients are typically asked to refrain from eating or drinking for up to 8 hours before a gastroscopy, and to inform the doctor in advance about any anticoagulants, iron supplements, or other medications they are taking. [14]

During the procedure, the patient lies on their side. The doctor passes an endoscope into the stomach and then into the duodenum, and inserts small forceps through the instrument channel to collect tissue. The NIDDK specifically emphasizes that the biopsy itself is usually not felt, and a UK guide from United Lincolnshire Hospitals states that it is not painful. [15]

The gastroscopy itself typically takes about 10-20 minutes, although the entire visit is longer due to preparation and observation after sedation. A local throat spray and intravenous sedation may be used for comfort. Some patients undergo the examination with local anesthesia alone, while others are more drowsy and relaxed. [16]

After the procedure, the patient is typically observed for about an hour if sedated. According to the NIDDK, short-term bloating, nausea, or sore throat are possible immediately after a gastroscopy, and the histology results themselves are available later, sometimes in a few days or longer, depending on the laboratory. Some UK guidelines recommend a wait time for a biopsy result of the procedure of 2 to 6 weeks. [17]

Stage	What's happening
Preparation	They clarify medications, illnesses, allergies, and the issue of sedation
Hunger pause	Usually do not eat or drink until 8 o'clock
Gastroscopy	The endoscope passes through the mouth into the stomach and duodenum
Tissue collection	Forceps are inserted through the endoscope and small samples are taken.
After the procedure	Observation, then discharge and waiting for histology

The table is based on materials from the NIDDK, NHS and United Lincolnshire Hospitals. [18]

What exactly does a biopsy show and how are the results read?

A histological assessment is not simply a statement of "disease or not." The pathologist evaluates the structure of the mucosal villi, whether they are shortened or lost, whether there is crypt elongation, inflammatory infiltration, and an increase in the number of intraepithelial lymphocytes. The ESPGHAN guidelines for pathologists explicitly state that the description should take into account the orientation of the biopsy specimen, the degree of villous atrophy, crypt elongation, the villus-to-crypt ratio, and the number of intraepithelial lymphocytes. [19]

If celiac disease is suspected, it is precisely this combination of features that determines the diagnostic value of a biopsy. ACG and BSG have emphasized for many years that changes in celiac disease can be focal, so it is important not only to correctly interpret the specimen but also to take it correctly. Due to the patchy nature of the disease, a single small biopsy can easily prove falsely reassuring. [20]

Many laboratories further group changes according to the Marsh-Oberhuber classification. Current ESPGHAN pediatric guidelines specifically state that Marsh 1 alone is not considered sufficient for the diagnosis of celiac disease, and that discrepancies between serology and morphology may require re-sampling or a second opinion from an experienced pathologist. This is important, as not every increase in lymphocytes indicates celiac disease. [21]

The sampling technique is also important. The ACG recommends taking 1-2 biopsies from the duodenal bulb and at least 4 biopsies from the distal portion of the duodenum if celiac disease is suspected. The NIDDK formulates the same rule more simply: biopsies should include both the bulb and the distal portion. British quality standards also require a minimum of 4 biopsies, including a sample from the bulb. [22]

Ultimately, a good duodenal biopsy result can confirm celiac disease, support the suspicion of another enteropathy, demonstrate eosinophilic inflammation, or, conversely, help rule out severe mucosal damage. However, it must be interpreted only in conjunction with blood tests, symptoms, diet at the time of examination, and endoscopic findings. Without this, even correct histology can be misinterpreted. [23]

What does a pathologist evaluate?	Why is this important?
Villi of the mucous membrane	Their shortening or disappearance indicates damage to the mucous membrane.
Crypts	Their elongation supports the diagnosis of enteropathy.
Intraepithelial lymphocytes	Their excess may be an early sign, but is not strictly specific.
Orientation of the sample	A poorly oriented biopsy is more difficult to interpret.
The bulb and distal part separately	Changes may be focal

The table summarizes the principles of pathological evaluation according to the ESPGHAN, ACG, BSG and NIDDK recommendations. [24]

Risks, complications and recovery

Gastroscopy with biopsy is considered a low-risk procedure. The NIDDK clearly states that complications are rare, and potential problems include reactions to sedatives, perforation of the upper gastrointestinal tract wall, and bleeding. Bleeding after a routine diagnostic biopsy is usually minor and self-limiting. [25]

Immediately after the examination, a person may experience bloating, mild nausea, or a sore throat. These symptoms are usually short-lived. If sedation was used, driving is prohibited, and pre-arranged transportation is required. British guidelines also remind that if sedation is used, it is advisable for an adult to accompany the patient after the procedure. [26]

Serious complications are indeed rare, but it's important to be aware of warning signs. The NIDDK recommends seeking immediate medical attention if, after a gastroscopy, you experience increasing chest or abdominal pain, difficulty breathing, trouble swallowing, bloody vomiting, black, tarry stools, or fever. This is no longer a "normal recovery" but a reason to rule out a complication. [27]

A routine diagnostic biopsy typically does not require a long recovery period. Most people return to normal activities the same day or the next, once the sedation has worn off and there are no unusual symptoms. Restrictions apply primarily to the 24 hours following sedation, not the biopsy itself. [28]

It's also important not to overestimate the risk of bleeding in people who simply have small mucosal samples taken. Serious bleeding is extremely uncommon with standard endoscopic mucosal biopsies, which is why the method is so widely used in outpatient diagnostics. However, if a person is taking anticoagulants or antiplatelet drugs, their regimen should be discussed beforehand, not after the procedure. [29]

What happens after a biopsy?	Usually	Reason to contact urgently
Sore throat	Often briefly	If it gets worse and makes it difficult to swallow
Bloating, slight nausea	Possible	If they grow
Bleeding	Usually absent or minimal	Bloody vomit, black stool
Abdominal pain	Minor discomfort is possible	Increasing pain
Temperature	Usually no	Fever after the procedure

The table is based on data from the NIDDK and the British patient information leaflet after gastroscopy. [30]

Special situations that make biopsy especially important

The most important special situation is suspected celiac disease after starting a gluten-free diet. In this case, both serology and morphology may yield false negative results. The ACG and BSG emphasize that tests and biopsies for diagnosing celiac disease should be performed while on a gluten-containing diet, otherwise the sensitivity of the test is reduced. [31]

The second special situation is childhood. Biopsy is still widely used in pediatrics, but in some children with very high serology, a biopsy-free diagnosis is possible. ESPGHAN indicates that this approach is acceptable in children with IgA tissue transglutaminase antibody levels at least 10 times the upper limit of normal and positive endomysial antibodies in another blood sample. The NIDDK specifically notes that a similar strategy has not yet been adopted in adult gastroenterology. [32]

The third situation is negative serology despite very convincing clinical findings. The NIDDK notes that 2-3% of patients with celiac disease may have negative serologic results. Therefore, a physician should not automatically stop testing if symptoms, family history, malabsorption, or endoscopic findings still appear suspicious. [33]

The fourth situation is a repeat biopsy. This is not necessary for everyone. However, if symptoms persist, the original diagnosis is questionable, the results were inconsistent, or there is a suspicion of refractory celiac disease, repeat tissue sampling may be part of a diagnostic review. The UK guidelines on celiac disease specifically allow for repeat duodenal sampling in patients with persistent symptoms. [34]

The fifth issue is the technical quality of the examination. Even a good gastroscopy can lose diagnostic value if too few samples are taken, they are incorrectly oriented, or the doctor fails to capture the intestinal bulb. This is why adherence to biopsy standards significantly increases the detection of celiac disease. This is one of the most underestimated, yet practically crucial aspects of the entire procedure. [35]

Special situation	Why is this important?
Gluten-free diet before examination	May distort both serology and histology
A child with very high serology	In some cases, a biopsy may not be necessary.
Adult with very high serology	Biopsy is still the standard
Negative serology with high suspicion	A biopsy may still be needed
Poor quality of material collection	Increases the risk of missing a diagnosis

The table summarizes special clinical situations according to the ACG, BSG, NIDDK and ESPGHAN. [36]

FAQ

Are a duodenal biopsy and a gastroscopy the same thing?
No. Gastroscopy is an endoscopic procedure for examining the upper gastrointestinal tract. A biopsy is an additional step during a gastroscopy, when small tissue samples are removed through the endoscope for laboratory testing. [37]

Is a biopsy painful?
Typically, the actual tissue collection process isn't felt as pain. Discomfort is more often associated with the passage of the endoscope and the air in the stomach and throat, rather than the doctor removing a small sample of mucous membrane. [38]

How many biopsies should be taken if celiac disease is suspected?
Current guidelines for optimal diagnosis recommend taking material from both the bulb and the distal region. ACG recommends 1-2 samples from the bulb and at least 4 from the distal region, while BSG requires a minimum of 4 biopsies, including the bulb. [39]

Is it possible to diagnose celiac disease without a biopsy?
This is not yet considered standard practice in adults. In children, it is acceptable in certain cases if antibodies are very high and confirmed by a second biopsy, but this approach should be determined by a pediatric gastroenterologist. [40]

Should I eat gluten before a biopsy?
Yes, if the examination is being performed for possible celiac disease and the doctor has not given other instructions. A gluten-free diet before the examination may lead to false-negative serology and histology results. [41]

How long does it take for results to be available?
The endoscopist can provide initial impressions immediately, but histological results take time. According to the NIDDK, this typically takes several days or longer, while British guidelines often list a range of 2 to 6 weeks. [42]

What diseases does this biopsy most often confirm?
In everyday practice, the main goal is to confirm or exclude celiac disease. However, a biopsy can also help find another cause of symptoms if serology is negative or the findings are atypical. [43]

When should you urgently seek medical attention after the procedure?
If you experience increasing chest or abdominal pain, bloody vomiting, black stools, fever, difficulty breathing, or worsening swallowing. These symptoms are not part of the normal recovery process. [44]

Key points from experts

Benjamin Lebwohl, MD, MS, is a professor of medicine and epidemiology, associate clinical chief of the Division of Digestive and Liver Diseases, and director of clinical research at the Celiac Disease Center at Columbia University. His current academic profile at Columbia emphasizes clinical and research work in celiac disease. This is important for the topic of duodenal biopsy because modern celiac disease diagnostics rely not on a single test but on the correct combination of serology, endoscopy, and qualitative morphology. [45]

Joseph A. Murray, MD, a gastroenterologist at the Mayo Clinic, is one of the most renowned celiac disease specialists, with a stated focus on celiac disease. The Mayo Clinic position and Joseph Murray's profile reflect a key practical conclusion: duodenal biopsy remains the cornerstone of adult celiac disease diagnosis, even in the era of more sophisticated serology. [46]

Alberto Rubio Tapia, MD, Director, Celiac Disease Program, Cleveland Clinic, is a gastroenterologist specializing in celiac disease. His official profile and Cleveland Clinic materials emphasize his specialization in celiac disease and its diagnostic pathways. This supports the article's clinical thesis: the higher the likelihood of celiac disease, the more important a high-quality, rather than a formal, duodenal biopsy is. [47]

Conclusion

A duodenal biopsy is not an "add-on" to a gastroscopy, but one of the most informative ways to confirm the status of the small intestinal mucosa. It is especially important when celiac disease is suspected, where visual inspection is insufficient and the quality of sample collection directly impacts the accuracy of the diagnosis. [48]

The key requirements for a useful biopsy are simple but essential: correct indications, a sufficient number of samples, sampling from the bulb and distal portion, maintaining a gluten-free diet prior to the examination, and a competent pathological evaluation. If any of these elements are missing, the diagnostic value of the procedure is diminished. [49]

The most practical idea for the patient is this: it's not a small tissue sample that should be feared, but a missed diagnosis. With a proper gastroscopy and biopsy, the risks are low, and the benefits can be enormous – from confirming celiac disease to ruling out a serious cause of chronic symptoms. [50]