Induced laryngeal obstruction test

This page contains information for patients who have been referred for an induced laryngeal obstruction test.

Illustration of laryngeal anatomy

Why do I need this test?

This test is required if your doctor thinks that you may have inducible laryngeal obstruction.  This means the vocal cords and/or structures

 around them become narrowed as a response to triggers, such as perfumes, dust, cleaning products or exercise.  

Symptoms that may suggest you have this condition can include breathlessness, noisy breathing, wheeze, cough, or changes in your voice.

Before the appointment

Phone the Respiratory Physiology team before your appointment if you have experienced any of the following:

  • Head, eye, mouth, chest, or abdominal surgery in the last 2 months. 
  • A chest infection, diagnosed by a medical professional, in the last 2 months.
  • A heart attack/stroke that occurred in the last 2 months.
  • A blood clot in your lung.
  • Coughing up blood in the last 2 weeks

What do I need to do on the day?

  • Do not drink any alcohol before testing.
  • Eat only a small meal.
  • Do not complete any strenuous exercise at least 30 minutes before your appointment.
  • Avoid potential triggers related to your symptoms.
  • Do not apply body lotions before the test.
  • Take all of your usual medications as prescribed before the test.

What do I need to bring?

You should bring your appointment letter.

If possible, you should bring the trigger/s of your symptoms. If they cannot be brought, then just phone our department on the number provided at the end of this leaflet. 

If you are being tested for exercise induced symptoms then exercise equipment will be provided – please bring clothes suitable to exercise in.

What happens during my appointment?

When you arrive in the Brunel building, please go to Gate 12 and check yourself in at the reception desk. When your name appears on the television screen, go to the Respiratory Physiology waiting room.

You will be invited into the testing room where you will have the chance to ask any questions and the details of the test will be explained to you. 

A simple breathing test will then be performed, and your oxygen levels measured by an oximeter being placed on one of your fingers. 

A thin tube with a small camera will be gently placed in and through your nose so your throat can be observed. A helmet will be placed on your head to hold the camera in place. If you are being tested for exercise-induced laryngeal obstruction, then stickers will also be placed on yourchest to look at your heart rhythm throughout the test.

The physiologist and doctor will then safely expose you to the symptom trigger in a controlled manner, while observing your vocal cords via the camera. 

What happens after my appointment?

After the test, we will inform you of the results and discuss a plan. This will be communicated to your GP via a letter, and you will receive a copy. 

Who can I contact for any queries or concerns?

If you have any problems or concerns about coming for this test or are going to be late, please do not hesitate to contact us:

Respiratory physiology team
Phone: 0117 414 5400

We are happy to talk to you about any issues or concerns you have about your appointment.

© North Bristol NHS Trust. This edition published April 2024. Review due April 2027. NBT003263. 

Induced laryngeal obstruction test