A Hill Grade 2 result is generally considered normal. The Hill classification is a four-point scale that endoscopists use to rate the appearance of the flap valve where your esophagus meets your stomach, and most gastroenterology research groups grades 1 and 2 together as the “normal” category while reserving grades 3 and 4 for the “abnormal” group. That said, grade 2 sits at a borderline that generates real confusion for patients and even some disagreement among researchers, which makes it worth understanding in more detail.
What the Hill Classification Describes
When a gastroenterologist performs an upper endoscopy, they can turn the camera backward (a maneuver called retroflexion) to look at the junction where the esophagus connects to the stomach. At that junction there is a fold of tissue that acts like a one-way flap valve: it helps keep stomach acid from washing back up into the esophagus. This structure, called the gastroesophageal flap valve (GEFV), was first systematically graded by Dr. Lucius Hill and colleagues, who developed the four-grade scale by examining both cadavers and living patients with and without reflux disease.1PubMed. The gastroesophageal flap valve: in vitro and in vivo observations
The flap valve is created by the angle at which the esophagus enters the stomach, and it extends a few centimeters along the lesser curve of the stomach. In cadaver studies, this fold produced a measurable pressure gradient at the junction even without any active muscle contraction, which demonstrated that the valve’s structure alone contributes to keeping acid where it belongs.2Journal of Clinical Gastroenterology. The Gastroesophageal Flap Valve The lower esophageal sphincter and the flap valve work together to form what is essentially a two-part anti-reflux barrier.3Journal of Surgery. Hill’s Classification of Gastro-Oesophageal Flap Valve Weakness – A Valuable Tool for Endoscopic Grading of Gastro-Oesophageal Reflux Disease
What Each Grade Looks Like
The four grades describe a spectrum from a tight, well-formed valve to one that is essentially absent. A grade 1 valve shows a prominent ridge of tissue that wraps snugly around the endoscope and runs several centimeters along the lesser curvature of the stomach. A grade 2 valve looks similar but the ridge is less pronounced, and it may briefly open during breathing before closing again.4Scientific Reports. Efficient artificial intelligence-based assessment of the gastroesophageal valve with Hill classification through active learning Grade 3 shows a fold that no longer hugs the scope closely, leaving the junction partially open. Grade 4 means the valve is essentially absent, with the junction gaping open and the esophagus visible without any surrounding fold.
The visual difference between a grade 1 and a grade 2 is subtle. You are looking at tissue that still forms a recognizable fold and still closes around the scope; it just does not grip quite as tightly, and it flutters open momentarily when the patient inhales.5PubMed Central. Gastroesophageal flap valve reflected EGJ morphology and correlated to acid reflux Compare that to the jump from grade 2 to grade 3, where the tissue visibly pulls away from the scope and the junction looks loose. The biggest functional gap in the scale falls between grades 2 and 3, which is why most clinical research draws the dividing line there.
Why Grade 2 Falls in the Normal Category
The most direct evidence that grade 2 belongs with grade 1 rather than grade 3 comes from a large study published in Diseases of the Esophagus that compared outcomes across all four Hill grades. The researchers found that grades 3 and 4 were associated with esophagitis, Barrett’s esophagus, symptoms of gastroesophageal reflux disease (GERD), and prescriptions for acid-suppressing medications, whereas there was no clinically meaningful difference between grades 1 and 2 on any of those measures.6Diseases of the Esophagus. What is the significance of the Hill classification? The study’s authors stated explicitly that distinguishing grade 1 from grade 2 was not important in clinical practice, while identifying grades 3 and 4 was important for predicting reflux complications and the need for ongoing medication.6Diseases of the Esophagus. What is the significance of the Hill classification?
Pediatric research echoes this grouping. A study of children suspected of having GERD categorized the flap valve as normal (grades 1 and 2) or abnormal (grades 3 and 4) and found that the abnormal group had significantly higher acid exposure and more reflux episodes on pH monitoring.7PubMed Central. Usefulness of Endoscopic Hill Grade in Evaluating Children Suspected of Having Gastroesophageal Reflux Disease Another pediatric study used the same two-group split, with the majority of children falling into grade 2 within the normal group.8PLOS ONE. Impacts of Endoscopic Gastroesophageal Flap Valve Grading on Pediatric Gastroesophageal Reflux Disease The consistency of this grouping across adult and pediatric literature gives it substantial weight.
The Minority View That Treats Grade 2 as Abnormal
Not every study draws the line in the same place. At least one research group studying reflux symptoms in the ear, nose, and throat realm classified only grade 1 as normal and lumped grades 2, 3, and 4 together as abnormal. In that study, about 31% of patients had a grade of 2 or higher. The framing matters here: these researchers were looking at laryngopharyngeal reflux (where stomach acid reaches the throat), a condition that may be triggered by even modest amounts of reflux that would not cause classic heartburn. So the threshold for “abnormal” was set deliberately low.
This is worth knowing because if your endoscopy report cites a study that uses this stricter grouping, a grade 2 result could be flagged as mildly abnormal. The broader gastroenterology literature, though, overwhelmingly treats grade 2 as within normal limits. If you see a grade 2 on your report and feel uncertain, the most useful question to ask your doctor is which grouping system they are using and why.
Why Endoscopists Do Not Always Agree on Grade 2
One practical problem with the Hill system is that grade 2 is the hardest grade for doctors to agree on. A recent study comparing the Hill classification with a newer grading system found that Hill grade 2 had the lowest agreement between different observers, with a concordance score of just 0.239. For context, grade 4 scored 0.730 on the same measure, meaning doctors looking at the same images almost always agreed when the valve was wide open but frequently disagreed about whether a mildly reduced fold was grade 1 or grade 2.9PubMed. The AFS Endoscopic Classification of Esophago-Gastric Junction Integrity is Superior to the Hill Classification in Terms of Interobserver Variability
This poor reproducibility is one reason the clinical distinction between grades 1 and 2 gets downplayed. If trained endoscopists looking at the same image cannot reliably tell grades 1 and 2 apart, building treatment decisions around that distinction would be shaky. Researchers are exploring alternative classification systems (the AFS classification, for instance) that may offer better consistency at the mild end of the spectrum, but for now the Hill system remains widely used.9PubMed. The AFS Endoscopic Classification of Esophago-Gastric Junction Integrity is Superior to the Hill Classification in Terms of Interobserver Variability Artificial intelligence tools are also being trained to standardize Hill grading from endoscopy images, which could eventually reduce the variability that plagues grade 2.4Scientific Reports. Efficient artificial intelligence-based assessment of the gastroesophageal valve with Hill classification through active learning
The Reflux Gradient Across Grades
Even though grades 1 and 2 are grouped as normal, the Hill scale does reflect a continuous gradient of acid exposure rather than a binary switch. In a pediatric study that measured reflux with 24-hour pH monitoring, each step up on the Hill scale was associated with a roughly 2% increase in acid exposure time, about 19 more reflux episodes per day, and about 10 more episodes of reflux reaching the upper esophagus.7PubMed Central. Usefulness of Endoscopic Hill Grade in Evaluating Children Suspected of Having Gastroesophageal Reflux Disease Those increases were statistically significant at every step, including the step from grade 1 to grade 2.
So does that mean grade 2 is riskier than grade 1? Technically, on average, a grade 2 valve lets slightly more acid through. But the real question is whether that small increment translates into symptoms or tissue damage, and the answer from the larger clinical studies is that it does not, at least not to any degree that changes diagnosis or treatment. The adult study discussed earlier found that rates of esophagitis in grade 2 patients were modestly higher than in grade 1 patients, but the difference was not statistically significant.6Diseases of the Esophagus. What is the significance of the Hill classification? Think of it like blood pressure: 118/78 is measurably different from 110/70, but both are considered normal and neither triggers treatment.
What This Means If You Are Having Symptoms
Getting a grade 2 result alongside heartburn or regurgitation does not mean the two are unrelated, but it does mean your flap valve is probably not the main culprit. Reflux disease involves multiple factors: how well the lower esophageal sphincter muscle contracts, how quickly your stomach empties, your body position after meals, abdominal pressure, and more. A grade 2 valve is doing its mechanical job adequately, so if you have bothersome reflux, your doctor will typically look at those other factors rather than focusing on the valve itself.
The practical difference matters most when surgery enters the conversation. Anti-reflux procedures like fundoplication or transoral incisionless fundoplication aim to reconstruct or reinforce the flap valve. These procedures make sense for patients with grades 3 or 4, where the valve is clearly disrupted. For someone with a grade 2 valve, surgical reinforcement of the valve would be hard to justify because the structure is still largely intact. Lifestyle adjustments, dietary changes, and if needed, acid-suppressing medications are the typical approach when symptoms coexist with a normal Hill grade.
Hill Grade Before Weight-Loss Surgery
One area where the Hill grade has gained specific clinical relevance is in predicting reflux after laparoscopic sleeve gastrectomy, a common weight-loss surgery. A multicenter study from Egypt found that while several endoscopic findings were associated with post-surgical GERD in initial analysis, the preoperative Hill grade emerged as the only independent predictor of reflux after the procedure.10PubMed Central. Preoperative Hill’s classification as a predictor of postoperative gastroesophageal reflux disease following laparoscopic sleeve gastrectomy: a prospective multicenter study from Egypt Sleeve gastrectomy reshapes the stomach and can alter the angle at which the esophagus enters it, potentially weakening the flap valve. Having a lower-grade (healthier) valve before surgery appears to offer some protection.
If you are being evaluated for sleeve gastrectomy and your preoperative endoscopy shows a grade 2, that is reassuring in this context. It suggests your flap valve anatomy is in reasonable shape going into the procedure. A grade 3 or 4 finding, by contrast, might prompt your surgeon to consider alternative approaches or to counsel you more carefully about post-operative reflux risk.
Hill Grade in Children
The Hill classification is used in pediatric endoscopy as well, and the normal-versus-abnormal grouping holds for younger patients. In one pediatric study of children suspected of having reflux disease, grade 2 was by far the most common finding in the normal group: out of 36 children classified as having a normal flap valve, 31 had grade 2 and only 5 had grade 1.8PLOS ONE. Impacts of Endoscopic Gastroesophageal Flap Valve Grading on Pediatric Gastroesophageal Reflux Disease The children with abnormal grades (3 and 4) had measurably worse reflux on monitoring, reinforcing that the meaningful clinical cutoff falls above grade 2 even in younger patients.
That finding also suggests that grade 2 may be the most common normal variant in children. A “textbook perfect” grade 1 valve seems to be less common than a grade 2 that still functions properly, which is useful context for parents who see the grade on their child’s report and wonder whether it indicates a problem.
When a Normal Finding Still Triggers Worry
A grade 2 result sometimes generates anxiety not because of what it means medically but because of how it appears on a report. Seeing any grading system that places you at “2 out of 4” can feel like you are halfway to the worst outcome. This reaction is a well-documented phenomenon with incidental or borderline findings across many areas of medicine. A national survey of physicians found that cascades of follow-up testing triggered by incidental findings caused psychological harm to patients in about two-thirds of cases, financial burden in over half, and physical harm in roughly one in six.11PubMed Central. Cascades of Care After Incidental Findings in a US National Survey of Physicians
The Hill grade context is important here: a grade 2 does not warrant additional testing on its own. If your endoscopy was done for reflux symptoms and the valve looks like a grade 2 with no esophagitis, that is a normal finding and not a reason for further endoscopic workup of the valve. A good clinician will note the grade in the report and move on to address whatever brought you in. If you find yourself anxious about the number, it is perfectly reasonable to ask your doctor to walk you through what the grade means and whether it changes anything about your care plan. In the vast majority of cases, it will not.
Could a Grade 2 Valve Worsen Over Time
There is limited longitudinal data tracking whether individual patients’ Hill grades change over years. What we know from cross-sectional studies is that the flap valve’s integrity correlates with factors like hiatal hernia, obesity, and aging. A hiatal hernia, where part of the stomach pushes up through the diaphragm, disrupts the angle of entry that creates the flap valve and can shift the grade upward. Sustained increases in abdominal pressure from significant weight gain could theoretically have a similar effect.
That said, the flap valve is an anatomical structure, not a muscle that atrophies from disuse. It does not “wear out” the way a joint might. A grade 2 valve in someone without a hiatal hernia, at a stable weight, is unlikely to spontaneously deteriorate to a grade 3 or 4. If your grade does change on a future endoscopy, it is more likely due to the poor interobserver agreement discussed earlier than to actual anatomical progression. The same valve might be called a 1 by one endoscopist and a 2 by another, or a 2 on one day and a 2 on the next. That ambiguity, ironically, is itself evidence that the difference between those two grades is clinically trivial.