Grading of GERD: Hill vs. AFS classification


Gastroesophageal Reflux Disease (GERD) is the most prevalent chronic esophageal disorder, characterized by discomfort and potential complications arising from stomach acid flowing back into the esophagus. The antireflux barrier (ARB), crucial in maintaining the integrity of the esophagus-stomach junction, deteriorates in GERD. Traditional endoscopic evaluations, notably the Hill grade classification focused on the “flap valve” mechanism at the esophagogastric junction (EGJ), have faced skepticism due to perceived subjectivity and inconsistency in application among clinicians.

The Hill Grade Classification

The Hill grade, established by Hill et al. in 1996, classifies the EGJ based on the endoscopic appearance of the flap valve. This method ranges from Grade I, indicating a tightly approximated gastroesophageal fold, to Grade IV, which signifies significant herniation and a wide diaphragmatic opening. Despite its pioneering approach, the Hill grade has been limited by its narrow focus and lack of standardization, leading to high interobserver variability.


  • Grade I: Tight approximation of the gastroesophageal fold against the endoscope.
  • Grade II: Loose grip of the gastroesophageal valve around the endoscope, with intermittent opening.
  • Grade III: Presence of a hiatal hernia, characterized by a visible gap between the squamocolumnar junction and the diaphragmatic crura.
  • Grade IV: Large hiatal hernia with a wider diaphragmatic opening.


  • Subjective, with significant interobserver variability.
  • Lacks precise measurements for hernia size or other anatomical details.
  • Focused solely on the flap valve without considering other anatomical disruptions at the EGJ.

The AFS Classification

The American Foregut Society (AFS) classification system is a significant advancement in the endoscopic evaluation of gastroesophageal reflux disease (GERD) and its impact on the integrity of the esophagogastric junction (EGJ). This new classification was developed to address the limitations of the traditional Hill grade, which focused primarily on the appearance of the flap valve and suffered from high interobserver variability due to its subjective nature. The AFS classification system aims to provide a more standardized and objective framework for assessing the anatomical features and functional integrity of the EGJ, thereby enhancing the diagnosis and management of GERD.

Key Features of the AFS Classification

1. Comprehensive Evaluation Criteria: The AFS classification integrates several anatomical and functional aspects of the EGJ, going beyond the simple visualization of the flap valve. It assesses:

  • Hiatal Hernia Axial Length (L): This is the vertical length of the hernia, measured in centimeters from the Z-line (the junction of esophageal and gastric epithelium) to the impression made by the diaphragmatic crura.
  • Hiatal Aperture Diameter (D): This measures the size of the opening at the diaphragm, again in centimeters. This parameter helps in quantifying the extent of the hiatal opening that can contribute to reflux.
  • Flap Valve Presence (F): This component is designated as F+ or F−, indicating the presence or absence of a gastroesophageal flap valve, which is a critical element in maintaining anti-reflux barrier function.

2. Grading System: The AFS classification categorizes the EGJ into four grades based on the severity of anatomical disruption:

  • Grade 1: Represents an intact EGJ with a normal flap valve and minimal hiatal diameter, typically around 1 cm. This is indicative of a fully functional antireflux barrier.
  • Grade 2: Signifies partial disruption with some loss of intra-abdominal esophageal length, a slightly looser hiatus (1-2 cm in diameter), and absence of the flap valve, indicating the beginning of barrier dysfunction.
  • Grade 3: Indicates moderate disruption with a hiatal axial length of up to 2 cm or a hiatal aperture of 2-3 cm, along with a missing flap valve. This grade points towards more significant anatomical changes that can affect reflux control.
  • Grade 4: Denotes complete disruption, with a hiatal axial length greater than 2 cm or a very wide hiatal aperture (>3 cm), and no flap valve. This severe level of disruption is associated with substantial reflux and related symptoms.

3. Color Coding System: To facilitate easy identification and communication among healthcare professionals, the AFS classification employs a color-coding scheme:

  • Green indicates a normal anatomy (Grade 1),
  • Yellow suggests mild disruption (Grade 2),
  • Orange indicates moderate disruption (Grade 3),
  • Red signifies severe disruption (Grade 4).

Clinical Implications

The AFS classification provides a clearer, more quantifiable method for assessing the EGJ, which is crucial for diagnosing GERD and deciding on the appropriate intervention, whether medical, endoscopic, or surgical. By reducing the subjectivity associated with the Hill grade and introducing quantifiable and observable criteria, the AFS system aims to decrease interobserver variability, thereby leading to more consistent clinical assessments and treatments. It also facilitates better communication among clinicians and researchers by providing a common language and visual tools.


  1. Nguyen NT, Thosani NC, Canto MI, et al. The American Foregut Society White Paper on the Endoscopic Classification of Esophagogastric Junction Integrity. Foregut 2022;2:339-348.
Last update: 2 May 2024, 22:32


Gastroenterologist - Hepatologist, Thessaloniki

PhD at Medical School, Aristotle University of Thessaloniki, Greece

PGDip at Universitair Medisch Centrum Utrecht, The Netherlands

Ex President, Hellenic H. pylori & Microbiota Study Group