What is the role of butanol threshold test in the diagnosis of taste and smell disorders?

Updated: Jan 08, 2021
  • Author: Eric H Holbrook, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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The butanol threshold test involves a forced-choice test using an aqueous concentration of butyl alcohol in one sniff bottle and water in the other. The patient is asked to identify the bottle containing the odorant, with each nostril tested separately.

After each incorrect response, the concentration of butanol is increased by a factor of 3 until the patient either achieves 5 correct responses or fails to correctly identify the bottle with 4% butanol.

The detection threshold is recorded as the concentration at which the patient correctly identifies the butanol on 5 consecutive trials. The scoring relates the patient's threshold to a normal subject population

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