Saliva Test for Laryngopharyngeal Reflux (LPR)

Various groups have been developing a fast, cheap, non-invasive saliva swab test to determine whether laryngopharyngeal reflux (LPR) is present or not. LPR may cause symptoms of:

• Hoarseness
• Chronic (ongoing) cough
• Frequent throat clearing
• Constant mucus or phelgm in the throat
• Dry or sandpaper like sensation in the throat
• Pain or burning sensation in the throat
• Feeling of a lump in the throat (globus pharyngeus)
• Problems swallowing
• Bad/bitter taste in the mouth (especially in morning)
• Asthma-like symptoms
• Ear pain and/or persistent ear infections
• Post-nasal drip
• Large lingual tonsils

When you compare a spit test to the current way of how reflux is determined via barium swallow, upper endoscopy (EGD), and 24 hour ph/impedance testing, it sounds quite attractive.

How does such a test work?

It basically looks for a stomach protein called pepsin.

Given reflux is when stomach contents moves up towards the mouth and pepsin is a protein ONLY produced in the stomach... pepsin should NOT be found in the throat/mouth.

As such, the test can state "yes" or "no" whether LPR is present or not. Keep in mind that this test does NOT inform what type of reflux is present whether acid reflux or non-acid reflux, nor does it reliably inform how severe the reflux is.  Only the 24 hour ph/impedance testing can provide such information.

How good is the test?

Depending on the study, sensitivity ranges in the 80-100% (can actually detect reflux if truly present) and specificity is around 85% (truly no reflux if test is negative).

Research published in 2021 suggests a nearly 90% correlation between a positive salivary pepsin test and 24 hour ph/impedance test.

One test company is RDbiomed in Europe using their Peptest kit.

The other is PepsinCheck here in the United States.

This test is currently not FDA approved.

You can order this test yourself as an individual. It is recommended you take the standard 3 sample test kit. Results typically take about 1 week.

References:
Sensitive pepsin immunoassay for detection of laryngopharyngeal reflux. Laryngoscope. 2005 Aug;115(8):1473-8.

Rapid salivary pepsin test: Blinded assessment of test performance in gastroesophageal reflux disease. Laryngoscope. 2012 Jun;122(6):1312-6. doi: 10.1002/lary.23252. Epub 2012 Mar 23.

Is Pepsin a Reliable Marker of Laryngopharyngeal Reflux? A Systematic Review. Otolaryngol Head Neck Surg. 2017 Sep;157(3):385-391. doi: 10.1177/0194599817709430. Epub 2017 Jun 6.

The Diagnostic Usefullness of the Salivary Pepsin Test in Symptomatic Laryngopharyngeal Reflux. J Voice. 2018 Oct 9. pii: S0892-1997(18)30081-X. doi: 10.1016/j.jvoice.2018.07.008. [Epub ahead of print]

Pepsin and oropharyngeal pH monitoring to diagnose patients with laryngopharyngeal reflux. Laryngoscope. 2019 Oct 11. doi: 10.1002/lary.28320. [Epub ahead of print] 

Diagnostic Utility of Salivary Pepsin as Compared With 24-Hour Dual pH/Impedance Probe in Laryngopharyngeal Reflux. Volume: 164 issue: 2, page(s): 375-380.