Restech – The Best Way to Diagnose LPR?

The Restech Dx-pH test is a 24-hour pH monitoring study that measures acidity in the throat (larynx) rather than the esophagus. It is currently the most reliable available test for diagnosing laryngopharyngeal reflux (LPR) because its probe stays hydrated and can detect both liquid and gaseous reflux — the type of reflux that standard pH tests routinely miss.

A thin tube is passed through the nose and positioned at the back of the throat, where it records pH levels continuously for 24 hours while you go about your normal day. The data is then analysed to determine whether abnormal acid exposure is occurring at the laryngeal level. Understanding what the test measures — and crucially what it doesn’t — is essential for interpreting results correctly.

Key Takeaways

• The Restech (Dx-pH) test measures throat pH over 24 hours — it is specifically designed to detect LPR, which standard esophageal pH tests consistently miss.
• Standard pH tests fail for LPR because their probes measure liquid acid in the esophagus, not gaseous reflux at the laryngeal level — where LPR damage actually occurs.
• The Restech probe maintains hydration, allowing it to detect both liquid and gaseous reflux reliably, making it far more sensitive for LPR diagnosis.
• Normal laryngeal pH is approximately 6.5–8.0; readings below this range, particularly when sustained, indicate abnormal acid exposure consistent with LPR.
• LPR reflux patterns look different from GERD on pH graphs — fewer events but longer in duration — which requires an experienced clinician to interpret correctly.
• The Restech has an important limitation: it measures acid, not pepsin — so a normal result doesn’t definitively rule out LPR, since pepsin can cause symptoms even with weakly acidic reflux.
• The Peptest is a complementary test that directly detects pepsin in saliva and can help confirm LPR when Restech results are borderline.
• PPIs are frequently prescribed after a positive Restech result but are largely ineffective for LPR — diet and Gaviscon Advance are the evidence-based first-line approach.

If you’ve been dealing with a chronic cough, persistent throat clearing, hoarseness, or a lump in the throat feeling, and standard investigations keep coming back normal — the Restech test may be the missing piece.

LPR is one of the most underdiagnosed conditions in ENT and gastroenterology practice, largely because the standard diagnostic tools weren’t built to detect it. The Restech Dx-pH system was. In this article I’ll walk through exactly how it works, how it compares to other pH tests, what the results mean, and what to do once you have a diagnosis.

How the Restech Test Works

The Restech procedure is straightforward, though it requires 24 hours of commitment. Here’s what happens step by step:

Probe placement. A thin, flexible catheter is passed through one nostril and positioned so the pH sensor sits at the level of the oropharynx — the back of the throat, just above the larynx. This is the critical difference from standard pH tests, which position the sensor in the esophagus. Placement at the laryngeal level is what makes Restech relevant to LPR, since this is where LPR-driven damage actually occurs.

The recording device. The catheter connects to a small wireless recorder worn around the neck or clipped to clothing. Throughout the 24-hour period, the sensor continuously logs the pH of the throat environment. You press event buttons on the recorder to mark meals, sleep periods, and symptom episodes — this context helps clinicians interpret the data meaningfully.

Normal activity. The test is designed to capture your real-world pattern, so you should eat, drink, and behave as normally as possible during the 24 hours. Artificially “good” behaviour during the test produces misleading results. Some clinicians will ask you to stop PPIs and certain medications for a period before the test to get an accurate baseline reading — follow their specific instructions on this.

Data analysis. After 24 hours the probe is removed and the data is downloaded and analysed. The software produces a graph of throat pH over time, which the clinician reviews alongside the symptom and meal markers you recorded.

What Normal and Abnormal Results Look Like

Normal pH in the larynx (throat) is approximately 6.5–8.0. The esophagus sits at around pH 7.0 at rest. Any sustained drops below these thresholds — particularly if they correlate with symptom episodes or post-meal periods — are indicative of abnormal acid exposure at the laryngeal level.

One important nuance is that LPR reflux patterns look different from GERD patterns on these graphs — and this is where interpretive skill matters enormously. In GERD, pH drops tend to be frequent, short, and clearly associated with meals or lying down. In LPR, events may be fewer but longer in duration, and they may occur at different times of day. Some clinicians, accustomed to interpreting GERD-pattern pH studies, may read an LPR-pattern result as “not significant” when it actually is [Vailati et al., Journal of Voice, 2013].

This is why finding a clinician experienced specifically with LPR and the Restech system matters — not just someone who has access to the equipment.

Why Restech Is Better Than Standard pH Tests for LPR

Standard pH monitoring tests — esophageal pH impedance studies and the Bravo wireless capsule — measure acid in the esophagus. They were designed to diagnose GERD, and they do that job reasonably well. But for LPR, they fail on two fundamental levels.

Wrong location. LPR damage occurs in the throat and larynx, not the esophagus. A sensor positioned in the esophagus doesn’t directly measure what’s happening three or four inches higher up, where the reflux is actually reaching.

Can’t detect gaseous reflux. LPR is predominantly driven by gaseous reflux — acid vapour and aerosolised pepsin that reaches the throat without producing the clear liquid acid spikes that esophageal tests are designed to detect. Standard pH probes can dry out at the laryngeal level and fail to register gaseous reflux reliably. The Restech probe is specifically engineered to maintain moisture at all times, allowing it to detect gaseous and liquid reflux with consistent sensitivity [Ayazi et al., Journal of the American College of Surgeons, 2010].

The practical consequence of these differences is significant. Many people with confirmed LPR have had standard pH studies come back completely normal — and been told they don’t have reflux. The Restech test was specifically developed to close this diagnostic gap.

Restech vs Standard pH Tests: Key Differences

Feature	Restech Dx-pH	Standard Esophageal pH Test
Probe location	Throat / larynx	Esophagus
Detects gaseous reflux	✓ Yes	✗ Unreliable
Best for diagnosing	LPR (silent reflux)	GERD / heartburn
Recording duration	24 hours	24–48 hours
Probe stays hydrated	✓ Yes (engineered)	✗ Can dry out at throat level
Detects pepsin directly	✗ No	✗ No

The Critical Limitation: Restech Doesn’t Detect Pepsin

This is something I want to be very clear about, because it’s the most important caveat when interpreting Restech results.

The Restech measures pH — it measures acidity. But LPR is not purely an acid problem. The real driver of LPR symptoms is pepsin — the digestive enzyme produced in the stomach that travels upward during reflux and deposits in throat tissue. Once there, pepsin causes inflammation and damage every time it’s reactivated by even mildly acidic exposures (anything below pH 5.0) [Johnston et al., The Laryngoscope, 2007].

The consequence of this is that someone can have a Restech result that falls within the “normal” pH range — and therefore be told they don’t have LPR — while still experiencing active pepsin-driven symptoms. The pH didn’t drop low enough to flag, but pepsin was still present and reactivating.

This is where the Peptest becomes a valuable complement to the Restech. The Peptest detects pepsin directly in saliva samples, providing evidence of LPR that doesn’t depend on pH thresholds. For people with borderline Restech results but persistent classic LPR symptoms, the Peptest can provide the diagnostic confirmation that the pH test couldn’t.

The honest clinical picture is this: the Restech is currently the best available first-line test for LPR — but a negative result doesn’t definitively rule the condition out, and pepsin detection is the logical next step when clinical suspicion remains high.

What to Do After a Positive Restech Result

A positive Restech — one showing abnormal acid exposure at the laryngeal level — confirms that reflux is reaching the throat. The next question is what to do about it, and this is where many people receive advice that doesn’t match the evidence.

The PPI Problem

The most common prescription after a confirmed LPR diagnosis is a course of proton pump inhibitors (omeprazole, lansoprazole, etc.). On the surface this seems logical — reflux is confirmed, so suppress the acid. The problem is that PPIs are largely ineffective for LPR specifically.

This isn’t a fringe position — it’s well supported in the literature. A placebo-controlled trial found PPIs no more effective than placebo for LPR symptoms over a 16-week treatment period [Koufman et al., The Laryngoscope, 2002]. The mechanism explains why: PPIs reduce acid production, but they don’t stop pepsin from being produced, don’t prevent weakly acidic or gaseous reflux from reaching the throat, and don’t remove the pepsin already deposited in throat tissue. For GERD, acid suppression is the right target. For LPR, it isn’t.

I’m not saying PPIs have no role — a short trial alongside dietary changes is reasonable in some cases. But if you’ve had a positive Restech, been prescribed PPIs, and aren’t seeing meaningful improvement after 8–12 weeks, that’s consistent with what the evidence predicts, and the focus should shift to the interventions that actually work for LPR.

What Actually Works for LPR

Diet — the most important intervention. Removing trigger foods and following a low-acid diet directly reduces pepsin reactivation in the throat. Every acidic food or drink below pH 5.0 that reaches the throat can reactivate pepsin already sitting in the tissue — removing those triggers breaks the cycle. I have detailed guidance on LPR foods to avoid and LPR foods to eat, and for a structured daily framework, the Wipeout Diet Plan was built specifically for LPR and GERD sufferers.

Gaviscon Advance (UK formulation). The UK version of Gaviscon Advance creates a physical alginate raft on top of stomach contents, mechanically blocking reflux from reaching the throat. This works independently of acid levels — it’s a physical barrier, not an acid suppressor — which is why it’s more directly relevant to LPR than PPIs. Take it after meals and at bedtime for the most effective protection. Full explanation in my Gaviscon Advance guide.

Lifestyle changes. Don’t eat within 3 hours of lying down. Keep portions small. Elevate the head of the bed for nighttime LPR. Reduce or eliminate alcohol, coffee, and soft drinks. These are foundational — no medication fully compensates for a lifestyle that’s chronically generating reflux events.

Surgery — for refractory cases. For people who have exhausted dietary and medical management without adequate relief, surgical options exist. The most commonly discussed for LPR are the Stretta procedure and Nissen fundoplication, covered in detail in my LPR surgery guide.

Availability and Cost of the Restech Test

The Restech test is more widely available in the United States than elsewhere, where it is offered at specialist ENT and gastroenterology centres. In the UK, it is not a standard NHS procedure but is available at some private hospitals and specialist reflux clinics. Availability in other countries varies significantly.

In the US, costs typically range from $300–$800 depending on the facility and whether the test is covered by insurance — coverage varies by insurer and requires a physician referral in most cases. In the UK, private costs are in the range of £300–£600.

If Restech is not available to you, the Peptest is a more widely accessible alternative that can be ordered online and completed at home. While it doesn’t provide the same 24-hour pH data, it directly detects pepsin in saliva and can provide meaningful diagnostic evidence where Restech isn’t an option.

Final Thoughts

The Restech Dx-pH test is the best available diagnostic tool for LPR — but it’s not perfect, and understanding its limitations is as important as understanding its strengths. A positive result provides clear evidence of abnormal acid reaching the throat and gives a solid foundation for targeted treatment. A negative result, however, doesn’t definitively rule LPR out — particularly when classic symptoms persist — and should prompt consideration of Peptest to look for pepsin directly.

If you’ve had a positive Restech and been prescribed PPIs with limited results, that’s expected and consistent with what the evidence shows. The focus should shift to the interventions that address pepsin-driven LPR directly: a structured low-acid diet, Gaviscon Advance, and lifestyle changes that reduce reflux frequency at the source.

The Wipeout Diet Plan gives you the complete dietary and lifestyle framework for LPR recovery in one place — it was built specifically for people in exactly this situation, who have a diagnosis and want to know precisely what to do next. If you’d prefer to work through your specific test results and symptom picture with me directly, a one-to-one consultation is also available.

Frequently Asked Questions

What is the Restech test?

The Restech (Dx-pH) test is a 24-hour pH monitoring study where a thin probe is placed at the back of the throat to measure acidity at the laryngeal level continuously. It is specifically designed to detect LPR (laryngopharyngeal reflux / silent reflux), which standard esophageal pH tests are poorly equipped to identify. The patient wears a small recorder throughout the day and presses event buttons to mark meals and symptoms.

Is the Restech test painful?

The Restech test is not painful. Probe insertion through the nose may cause brief discomfort or a gagging reflex, which typically settles within a few minutes of placement. Once in position, most people adjust to the probe relatively quickly and are able to go about their normal day. Some people find it mildly uncomfortable to sleep with the probe in place, though this varies.

What is normal pH in the throat and esophagus?

Normal resting pH in the esophagus is approximately 7.0. In the larynx (throat), the normal range is approximately 6.5–8.0. Sustained pH readings below these thresholds, particularly in association with meals or lying down, are indicative of abnormal acid exposure consistent with LPR or GERD.

Can Restech miss LPR?

Yes — Restech can miss LPR in certain cases. Because it measures pH rather than pepsin directly, it may not flag cases where weakly acidic or gaseous reflux is carrying enough pepsin to cause symptoms without producing a significant pH drop. A normal Restech result with persistent LPR-type symptoms should prompt consideration of the Peptest, which detects pepsin directly in saliva samples.

How does Restech compare to the Peptest?

They measure different things. Restech measures the pH of the throat over 24 hours and identifies abnormal acid exposure. The Peptest detects pepsin — the enzyme responsible for LPR tissue damage — directly in saliva samples. Restech provides a comprehensive picture of reflux patterns; Peptest provides direct evidence of pepsin presence. Ideally both are used together for the most complete diagnostic picture, but Peptest is more accessible (it can be done at home) and may be the more informative test for some people.

Does LPR come and go?

Yes — LPR symptoms often fluctuate. Periods of higher symptom activity typically correlate with dietary triggers, stress, illness, or lifestyle factors that increase reflux frequency. With consistent management — particularly dietary changes and Gaviscon Advance — most people see their symptoms reduce and stabilise over weeks to months. Some people experience complete resolution; others manage to a low-symptom baseline that doesn’t significantly affect daily life.

Can I get a Restech test in the UK?

The Restech test is not available as a standard NHS procedure but is offered at some private ENT and reflux specialist clinics in the UK. If you’re unable to access Restech, the Peptest is a more widely available alternative that can be ordered directly and completed at home. Discussing referral options with your GP or asking for a specialist ENT referral is the recommended starting point.

Related Articles

• The Complete Guide to LPR (Silent Reflux)
• LPR Symptoms – How to Identify Silent Reflux
• Peptest – Detecting Pepsin to Diagnose LPR
• Why Gaviscon Advance Is Better for LPR Than Standard Gaviscon
• LPR Foods to Avoid – What to Cut Out for Silent Reflux
• LPR Surgery Options Explained
• Acid Reflux & GERD – The Complete Guide

Research Sources

LPR reflux events recorded via Restech differ in pattern from GERD — fewer events of longer duration — requiring specific interpretive expertise for accurate diagnosis [Vailati et al., Journal of Voice, 2013]. The Restech Dx-pH probe maintains probe hydration and detects gaseous reflux reliably, unlike standard esophageal probes which dry out and miss gas-phase acid events at the laryngeal level [Ayazi et al., Journal of the American College of Surgeons, 2010].

Pepsin deposited in throat tissue reactivates on contact with environments below pH 5.0, driving the ongoing inflammation and symptom cycle in LPR independently of active reflux events [Johnston et al., The Laryngoscope, 2007]. Proton pump inhibitor therapy has been demonstrated to be no more effective than placebo for LPR-specific symptoms in placebo-controlled trials, consistent with the pepsin-driven rather than acid-volume-driven mechanism of LPR [Koufman et al., The Laryngoscope, 2002].