Hiatal hernias are most commonly diagnosed with a barium swallow X-ray, which remains the preferred and most definitive test. Many hiatal hernias are also discovered incidentally during an upper endoscopy performed for other reasons, such as investigating acid reflux or chest pain. The specific test your doctor orders depends on your symptoms, their severity, and whether the goal is simply confirming the hernia or evaluating complications like reflux damage.
Understanding What’s Being Diagnosed
A hiatal hernia occurs when part of your stomach pushes up through the hiatus, the natural opening in your diaphragm where your esophagus passes through. There are four types, and knowing which one you have matters because it changes how urgent treatment is.
The vast majority are Type 1, or sliding hiatal hernias. In this version, the junction where your esophagus meets your stomach slides up through the opening and then back down. These are common, often small, and frequently cause no symptoms at all. Types 2 through 4 are paraesophageal hernias, meaning part of the stomach (or in Type 4, another organ like the spleen or intestine) pushes up alongside the esophagus rather than sliding along it. These are less common but more likely to need surgical repair because sections of the stomach can become trapped or lose blood supply.
Barium Swallow: The Primary Diagnostic Test
A barium swallow (also called an upper GI series) is the gold standard for diagnosing hiatal hernias. You drink a thick, chalky liquid containing barium, which coats your esophagus and stomach and makes them clearly visible on X-ray. A radiologist watches the barium travel down in real time using fluoroscopy, essentially an X-ray video, which lets them see movement and positioning as you swallow.
During the test, you’ll lie on an X-ray table and be asked to change positions: on your back, your side, your stomach. Being positioned face down (prone) actually makes sliding hiatal hernias easier to spot than standing upright, because gravity encourages the stomach to push upward through the hiatus. The radiologist looks for the location of the junction between your esophagus and stomach relative to the diaphragm. If a specific anatomical landmark called the mucosal B ring sits more than 1 to 2 centimeters above the diaphragm’s impression on the X-ray, a sliding hiatal hernia is confirmed.
The whole procedure typically takes 15 to 30 minutes. It’s noninvasive, requires no sedation, and gives a clear anatomical picture of where the hernia is, how large it is, and what type it is. For paraesophageal hernias, the barium swallow can show the stomach bulging alongside the esophagus rather than below it.
Upper Endoscopy
An upper endoscopy (sometimes called an EGD) involves passing a thin, flexible camera through your mouth, down your esophagus, and into your stomach. While it’s not the primary tool for diagnosing a hiatal hernia, it’s extremely useful because it lets doctors see tissue damage from acid reflux, check for inflammation, and take biopsies if needed. Many hiatal hernias are first noticed during an endoscopy ordered for reflux symptoms.
During the procedure, the doctor looks for specific visual markers. One key assessment involves a retroflexed view, where the camera is turned back on itself inside the stomach to look upward at the junction between the esophagus and stomach. In a healthy anatomy, a prominent fold of tissue wraps snugly around the scope. Doctors grade what they see on a four-point scale. At the mildest end, the tissue fold is present and grips the scope tightly. At the most severe grade, the fold is absent entirely, there’s a visible open space around the scope, and a hiatal hernia is always present. This grading system helps determine both the presence and severity of the hernia.
Endoscopy requires sedation and takes about 15 to 20 minutes. It’s particularly valuable when your doctor needs to assess not just the hernia itself but how much damage it may be causing to the lining of your esophagus.
Pressure Testing With Manometry
Esophageal manometry is a specialized test that measures pressure along your esophagus. It’s not a first-line diagnostic tool for hiatal hernias, but it can detect them with precision and is often used before anti-reflux surgery to map the anatomy and function of the area.
The test works by identifying two distinct pressure zones: one created by the muscular valve at the bottom of your esophagus, and another created by the diaphragm muscle where it wraps around the esophagus. In healthy anatomy, these two pressure zones sit in essentially the same spot. When a hiatal hernia is present, they separate. A gap of more than 1 centimeter between these two pressure signals reliably indicates a hiatal hernia, and surgical findings confirm this threshold. A gap of 2 centimeters or more suggests a larger hernia.
High-resolution manometry can also reveal whether the diaphragm muscle is still functioning as an effective barrier against reflux. In smaller hernias, the diaphragm typically still does its job. In larger hernias, the opening has widened enough that the diaphragm loses its ability to act as a secondary valve, which helps explain why larger hernias tend to cause worse reflux symptoms.
CT Scans and When They’re Used
CT scans aren’t the go-to test for diagnosing a typical hiatal hernia, but they play an important role in specific situations. Large paraesophageal hernias, where a significant portion of the stomach (or other organs) has pushed into the chest cavity, often show up clearly on CT. Emergency scenarios where the stomach may be trapped or twisted also call for CT imaging because of its speed and ability to show complications like reduced blood flow.
Many hiatal hernias are actually discovered by accident on CT scans ordered for unrelated reasons, such as evaluating chest pain or lung issues. If a hernia is found this way, your doctor will typically follow up with a barium swallow or endoscopy to get more detailed information.
Why Chest Pain Needs Careful Evaluation
Hiatal hernias can cause chest pain that feels alarmingly similar to a heart attack. The pain can be sharp, pressure-like, and located right behind the breastbone. Even experienced doctors cannot reliably distinguish between the two based on symptoms and a physical exam alone. If you go to an emergency room with chest pain, cardiac causes will be ruled out first with an electrocardiogram and blood tests before any evaluation for a hiatal hernia begins. This is standard practice regardless of your medical history.
Once heart problems are excluded, the diagnostic path shifts to the tools described above. Persistent chest pain alongside reflux symptoms, difficulty swallowing, or a feeling of fullness after small meals are the combinations that most often prompt testing for a hiatal hernia.
Which Test You’re Likely to Get
If your doctor suspects a hiatal hernia based on your symptoms, you’ll most likely start with a barium swallow. It’s the most direct and definitive way to confirm the diagnosis and see exactly what type you have. If you’re already scheduled for an endoscopy to evaluate reflux or esophageal symptoms, the hernia will typically be assessed during that same procedure.
Manometry is reserved for more complex situations, particularly when surgery is being considered or when your doctor needs to understand how well your esophagus is functioning. CT scans come into play for emergencies or when a large, complicated hernia is suspected. In many cases, a single test is enough to confirm the diagnosis and guide the next steps.