How to Diagnose Silent Reflux: A Complete Guide to LPR Testing and Management

Laryngopharyngeal reflux (LPR)—commonly known as silent reflux—is a condition where stomach contents flow back into the throat, larynx, and upper airway. Unlike typical gastroesophageal reflux disease (GERD), which often causes heartburn and regurgitation, LPR presents with subtle, easily overlooked symptoms that can lead to chronic throat issues, voice problems, and respiratory complications. Because many patients never experience classic heartburn, LPR frequently goes undiagnosed or is mistaken for allergies, asthma, or post-nasal drip.

 

This guide provides a comprehensive overview of how silent reflux is diagnosed, from recognizing the symptoms to understanding the latest objective testing methods, including emerging non-invasive pepsin detection.

 

What Is Silent Reflux (LPR)?

LPR occurs when gastroduodenal contents—including acid and the digestive enzyme pepsin—reflux into the upper aerodigestive tract, causing morphological and neurological changes in the pharynx, larynx, and even the nasal passages ^[1]. Unlike the esophagus, the tissues of the throat and voice box lack a robust protective lining, making them highly vulnerable to even small amounts of refluxate.

 

The term “silent” reflects the absence of typical GERD symptoms such as heartburn and regurgitation. Instead, LPR produces throat-centered symptoms that many patients do not immediately associate with stomach issues, creating a significant diagnostic challenge.

 

Recognizing the Signs: Key LPR Symptoms

Accurate diagnosis begins with recognizing the clinical picture. The most common symptoms of silent reflux include:

 

• Hoarseness or voice changes – A raspy, strained, or weak voice, particularly in the morning or after speaking
• Chronic cough – A persistent dry cough that does not resolve with typical treatments
• Frequent throat clearing – Often the most common symptom, as the body attempts to clear perceived irritation
• Globus sensation – The feeling of a lump in the throat that does not go away with swallowing
• Excess throat mucus or post-nasal drip sensation
• Difficulty swallowing (dysphagia)
• Sore throat – Without signs of infection

 

Because these symptoms overlap with many common conditions, LPR is frequently misdiagnosed. A high index of suspicion is essential, especially when patients do not respond to treatments for allergies, asthma, or sinusitis.

 

The Diagnostic Pathway for Silent Reflux

Diagnosing LPR typically involves a stepped approach, moving from clinical assessment to objective testing when needed.

 

Step 1: Clinical Assessment and Symptom Scoring

The initial evaluation begins with a thorough medical history and physical examination. Physicians often use standardized scoring tools:

• Reflux Symptom Index (RSI) – A nine-item patient-reported questionnaire that scores symptoms such as hoarseness, throat clearing, and globus sensation. An RSI score above 13 is suggestive of LPR.
• Reflux Finding Score (RFS) – Completed by a physician during laryngoscopy, this tool assesses physical signs in the larynx including edema, erythema, and vocal fold changes. An RFS score above 7 supports an LPR diagnosis.

 

These scoring systems provide a standardized framework for initial assessment, though they are subjective and do not confirm the presence of reflux objectively.

 

Step 2: Laryngoscopy

Laryngoscopy involves passing a flexible or rigid scope through the nose or mouth to directly visualize the larynx and pharynx. The physician looks for signs of inflammation, edema, erythema, and other characteristic findings of LPR. While laryngoscopy provides valuable visual information, it cannot definitively prove that reflux is the cause of observed changes, as other conditions can produce similar findings.

 

Step 3: Objective Diagnostic Testing

When clinical assessment is inconclusive or symptoms are severe, objective testing is recommended.

 

24-Hour Multichannel Intraluminal Impedance-pH Monitoring (MII-pH)

MII-pH monitoring is currently considered the gold standard for diagnosing LPR. This test involves placing a thin catheter through the nose into the esophagus and pharynx, where sensors continuously measure pH and impedance over 24 hours. More than one pharyngeal reflux event detected during MII-pH monitoring is diagnostic for LPRD ^[1]. The test has the advantage of detecting all types of reflux episodes—acidic, weakly acidic, and alkaline.

 

However, MII-pH is invasive, expensive, not widely available, and can be uncomfortable for patients. These limitations have driven interest in alternative diagnostic approaches.

 

Oropharyngeal pH Monitoring (DX-pH)

A less invasive alternative uses a small probe placed in the back of the throat to measure pH over 24 hours. Diagnostic criteria include a Ryan index greater than 9.41 in the upright position or greater than 6.79 when lying down. While more patient-friendly than MII-pH, this method detects only acidic reflux and may miss alkaline or weakly acidic events.

 

Salivary Pepsin Testing (Emerging Non-Invasive Approach)

In recent years, salivary pepsin detection has emerged as a promising, completely non-invasive diagnostic tool for LPR. Pepsin is a digestive enzyme produced exclusively in the stomach. Its presence in saliva serves as an objective biomarker of gastric content reaching the upper aerodigestive tract.

 

A 2025 systematic review published in the Journal of Voice analyzed 38 studies involving over 3,000 patients and found that salivary pepsin measurement has significant diagnostic value for LPRD ^[2]. The review noted that multiple saliva measurements throughout a 24-hour period improved test sensitivity and specificity.

 

A 2025 prospective study comparing saliva pepsin testing with standardized symptom and sign scoring systems reported excellent performance: against the Reflux Symptom Score questionnaire, saliva pepsin testing demonstrated 100% sensitivity and 90% specificity at a cutoff value of ≥16 ng/mL. Against the Reflux Sign Assessment, sensitivity was 95.24% with specificity of 88.89% ^[3].

 

Another 2025 study from India evaluated 94 patients with LPR and found that 85.1% tested positive for salivary pepsin at a cutoff of 50 ng/mL, with a strong correlation between pepsin levels and objective laryngeal findings seen on videolaryngoscopy ^[4].

 

Advantages of Pepsin Testing:

• Completely non-invasive – no catheters or scopes
• Rapid results – available within 15 minutes
• Objective evidence – detects pepsin, a biomarker specific to gastric reflux
• Cost-effective – significantly less expensive than MII-pH
• Can detect non-acidic reflux – pepsin remains stable regardless of pH

 

Diagnosing Silent Reflux with PEPFAST

For healthcare providers and patients seeking a practical, non‑invasive diagnostic option, Maxhealth Innovative Meditech offers the Pepfast salivary pepsin test kit – a ready‑to‑use solution based on the lateral flow technology discussed above. The test requires only a small saliva sample, delivers results within 15 minutes, and needs no centrifugation or laboratory equipment. By detecting the presence of pepsin – a biomarker exclusive to gastric reflux – Pepfast provides objective evidence to support the clinical diagnosis of LPR and GERD, making it a valuable tool in both specialist and primary care settings.

 

❓Frequently Asked Questions

 

Q1: How is silent reflux different from GERD?

Silent reflux (LPR) primarily affects the throat, larynx, and upper airway, whereas GERD primarily affects the lower esophagus. Classic GERD symptoms include heartburn and regurgitation. LPR symptoms include hoarseness, chronic cough, throat clearing, and globus sensation—often without any heartburn. The tissues affected by LPR are more sensitive than the esophagus, meaning even small amounts of reflux can cause significant symptoms.

 

Q2: Is there a non-invasive test for LPR?

Yes. Salivary pepsin testing is a completely non-invasive option. It requires only a small saliva sample and provides results within 15 minutes. Multiple studies have validated its diagnostic accuracy, with sensitivity ranging from 76% to 100% depending on the cutoff value and population studied ^[2][3].

 

Q3: How long does LPR testing take?

It depends on the method. Laryngoscopy takes about 5–10 minutes. Salivary pepsin testing provides results within 15 minutes. Oropharyngeal pH monitoring requires 24 hours of data collection. MII-pH monitoring also requires 24 hours, with additional time for data analysis.

 

References:

[1] Lechien JR, et al. European clinical practice guideline: managing and treating laryngopharyngeal reflux disease. European Archives of Oto-Rhino-Laryngology. 2024;283(1):629-641.

[2] Hiernaux A, Trelcat A, Lechien JR. Salivary Pepsin Measurement in Laryngopharyngeal Reflux Disease: A Systematic Review of Diagnostic Accuracy and Performance. Journal of Voice. 2025.

[3] Kandhi PW, Manurung R, Wicaksono P. Salivary pepsin detection for laryngopharyngeal reflux diagnosis: sensitivity and specificity comparison with scoring system. Oto Rhino Laryngologica Indonesiana. 2025;55(1).

[4] Liu C, Hou C, Chen T, et al. Diagnostic value of fasting hypopharyngeal salivary pepsin concentration test for laryngopharyngeal reflux disease. World Journal of Otorhinolaryngology. 2024.