There are no objective standards for diagnosing problems with reflux. As a result, a diagnosis typically relies on the physician’s judgment. In some cases, physicians can diagnose reflux very easily. For example, babies who regularly spit up large portions of food after meals and who fail to gain weight normally are usually diagnosed with reflux. On the other hand, reflux is sometimes trickier to diagnose, particularly in older children. Many of the symptoms associated with reflux – such as upset stomach or persistent vomiting – can be the result of an unrelated disorder.

A physician will perform a complete physical examination and compile a thorough medical history. To rule out anatomical abnormalities, a physician may order an x-ray of the esophagus and the stomach. The child may be asked to swallow barium, a chalky substance that highlights structures inside the body on x-rays and helps reveal any abnormalities.

Other tests may include:

• Endoscopy.  One of the most common tests used to evaluate the esophagus. A small tube with a light and camera (endoscope) is inserted into the esophagus, stomach and into a portion of the small intestine. This allows a physician to determine whether there is tissue damage. Samples of tissues may be taken (biopsy) to determine the extent of the damage.
  
  
• Esophageal pH monitoring. This is the most sensitive test for diagnosing reflux problems. It involves passing a thin tube through the nose and into the esophagus. The tube is attached to a small monitoring device and is worn for 24 hours. The device records how much stomach acid reaches the esophagus. There is a newer method that allows pH recording without the need for a tube through the nose (Bravo capsule device). The patient records symptoms experienced during the 24-hour period and the physician compares acid levels with symptoms. This is typically performed when an endoscopy is inconclusive or a patient continues to experience symptoms after receiving treatment.
  
  
• Esophageal manometry. Involves a device similar to the pH monitor that measures muscle contractions to determine whether the lower esophageal sphincter (LES) is functioning properly. This is typically performed when the diagnosis is unclear and surgery is being considered.

In addition, parents may be asked to keep a diary to record the child’s symptoms and any relevant details associated with them.

Gastroesophageal reflux disease (GERD) is generally diagnosed in children who have reflux that causes some measurable physical damage to the esophagus or other area of the body. A diagnosis of GERD may also be associated with significant medical problems, such as asthma, sinus or ear infections, apnea, significantly low weight gain, or inflammation of the esophagus (esophagitis).

GERD is also sometimes diagnosed solely on the basis of extreme misery that a child experiences as a result of reflux. For example, some children may experience significant pain or other discomfort from an occasional bout of reflux.