Gastroscopy (EGD): Indications, Preparation, and Early Diagnosis

What is EGD (Gastroscopy)?

Esophagogastroduodenoscopy (EGD), or gastroscopy, is the "gold standard" for diagnosing diseases of the upper gastrointestinal (GI) tract. This procedure allows an endoscopist to visually assess the condition of the mucous membrane of the esophagus, stomach, and duodenum [2].

During an EGD, a thin, flexible endoscope equipped with a camera and a light source is used. It is inserted through the oral cavity and allows for a detailed image of the internal organs to be displayed on a monitor. In addition to visual inspection, EGD provides the opportunity to perform a biopsy (taking tissue samples for histological examination), remove polyps, or stop bleeding, making it not only a diagnostic but also a therapeutic tool [2].

Main indications for EGD

EGD is prescribed for a wide range of symptoms and conditions that require detailed examination of the upper GI tract. The main indications include:

• Chronic or recurrent symptoms: Heartburn, pain in the upper abdomen (epigastrium), nausea, vomiting, difficulty swallowing (dysphagia), unexplained weight loss [5].
• Suspected peptic ulcer disease or inflammatory processes: Gastritis, esophagitis, duodenitis.
• Anemia of unknown origin: To rule out bleeding from the upper GI tract.
• Screening and surveillance of precancerous conditions: In patients with an increased risk of developing stomach cancer, for example, with chronic atrophic gastritis, intestinal metaplasia, or dysplasia. Endoscopic surveillance plays a key role in the early detection and timely intervention for these conditions [1, 7].
• Diagnosis of Helicobacter pylori infection: EGD allows for the collection of samples to confirm the presence of the bacterium, which is associated with peptic ulcer disease and the risk of developing stomach cancer [4].
• Exclusion of mechanical obstruction: In cases of symptoms indicating delayed gastric emptying, such as diabetic gastroparesis, EGD helps to rule out physical obstructions [3].
• Monitoring treatment efficacy: Assessing the healing of ulcers or erosions after therapy.
• Removal of foreign bodies.

How to prepare for an EGD: key steps

Proper preparation for an EGD is critical for the accuracy of the examination and patient safety. Failure to follow recommendations may lead to the need for a repeat procedure.

1. Fasting: This is the most important step. The procedure is performed strictly on an empty stomach. It is necessary to refrain from eating for 8-12 hours before the examination. The last meal should be light.
2. Avoidance of fluids: 2-4 hours before the procedure, all fluid intake, including water, should be completely excluded. Smoking is also not recommended, as it can stimulate the production of gastric juice.
3. Medications: Be sure to discuss your regular medications with your doctor. It may be necessary to temporarily discontinue certain drugs, especially blood thinners (anticoagulants), or adjust the insulin dose for patients with diabetes.
4. Informing the doctor: Inform your doctor about all your chronic diseases, allergies, past surgeries, and medications you are taking.
5. Escort: If the procedure is to be performed under sedation (medicated sleep), you must arrange in advance for someone to accompany you home, as driving is prohibited after sedation.
6. Psychological preparation: Try to relax. Modern endoscopes are very thin, and the procedure takes only a few minutes.

The significance of EGD in early diagnosis and prevention

EGD plays an indispensable role in the early detection of serious diseases, especially stomach cancer. Despite significant progress in understanding its pathophysiology and risk factors, stomach cancer remains a serious global public health problem [1]. Early detection is crucial for improving the prognosis [5].

Endoscopic technologies are constantly improving, which increases the potential for early diagnosis [1]. EGD allows for the detection of precancerous conditions, such as atrophic gastritis, intestinal metaplasia, and dysplasia, at early stages when timely intervention and prevention of malignant tumor development are possible [7]. However, it is important to remember that even with a thorough examination, some early lesions may be missed, especially in anatomically complex areas such as the incisura angularis, which is considered a high-risk zone for neoplasia [5]. This underscores the importance of the endoscopist's qualifications and the use of modern examination methods.

Potential risks and when a repeat EGD is required

EGD is a relatively safe procedure, but like any medical intervention, it has minimal risks. These include a mild sore throat, minor bleeding (especially after a biopsy), or, in very rare cases, perforation of the esophagus or stomach. Serious complications are extremely rare.

A repeat EGD may be recommended in the following cases:

• Persistence or worsening of symptoms: If, after an initial EGD that did not reveal significant abnormalities, symptoms persist or intensify [5].
• Surveillance of identified conditions: To monitor the healing of ulcers, the dynamics of polyps, and precancerous changes (atrophy, metaplasia, dysplasia) [7].
• Assessment of treatment efficacy: To ensure that the prescribed therapy is producing the desired result.
• Appearance of new symptoms: If new alarming symptoms arise that may indicate the development of another disease or the progression of an existing one.

Conclusion

Gastroscopy (EGD) is a highly informative and safe examination method that is a cornerstone in the diagnosis and treatment of upper GI tract diseases. Timely EGD, especially in the presence of alarming symptoms or risk factors, allows for the detection of pathologies at early stages, which significantly improves the prognosis and quality of life for patients. Proper preparation for the procedure ensures its maximum effectiveness and safety.

Sources

1. Early detection of gastric cancer: linking epidemiology, pathophysiology, and innovations in digestive endoscopy. (Diseases (Basel, Switzerland), 2026) https://pubmed.ncbi.nlm.nih.gov/42041640/
2. Characteristics and outcomes in patients undergoing esophagogastroduodenoscopy in Gaza hospitals: a retrospective study. (BMC gastroenterology, 2025) https://pubmed.ncbi.nlm.nih.gov/41419831/
3. Prevalence and clinical determinants of diabetic gastroparesis in type 2 diabetes mellitus: a cross-sectional study based on symptoms and scintigraphy. (BMC gastroenterology, 2026) https://pubmed.ncbi.nlm.nih.gov/42298424/
4. Validation of an H. pylori diagnostic approach based on gastric juice analysis. (Diagnostics (Basel, Switzerland), 2026) https://pubmed.ncbi.nlm.nih.gov/41750669/
5. Gastric adenocarcinoma missed at the incisura angularis during primary endoscopy: a case report. (Clinical medicine insights. Case reports, 2026) https://pubmed.ncbi.nlm.nih.gov/42396373/
6. Asian Pacific Association of Gastroenterology guidelines for the surveillance of Helicobacter pylori-associated gastric precancerous conditions. (Gut, 2026) https://pubmed.ncbi.nlm.nih.gov/41057234/

The information provided in this article is for reference purposes only and cannot replace an in-person consultation with a qualified medical professional. Always consult a doctor for diagnosis and treatment planning.