Alcohol Sniff Test (AST): An Important Tool for Screening Post-Viral Olfactory Loss in Acute Flu-Like Dysfunction.

Area of Science:

• Otolaryngology
• Neurology
• Infectious Diseases

Background:

• Olfactory disorders significantly impact quality of life but are often overlooked.
• Upper respiratory tract infections (URTIs) commonly cause olfactory loss, with post-viral olfactory dysfunction (PVOD) persisting after symptom resolution.
• PVOD results from damage to olfactory pathways, necessitating effective diagnostic tools.

Purpose of the Study:

• To evaluate the Alcohol Sniff Test (AST) as a predictor of post-viral olfactory loss in patients presenting with flu-like syndrome.
• To assess the AST's ability to differentiate PVOD from conductive olfactory disorders in the acute phase of illness.

Main Methods:

• An observational cross-sectional study involving employees with flu-like syndrome at a tertiary hospital.
• Three groups were established: PVOD- (flu-like, conductive disorder, no COVID-19), PVOD+ (flu-like, neurosensory/central disorder, COVID-19), and asymptomatic controls.
• The Alcohol Sniff Test (AST) was administered to assess olfactory function, followed by statistical analysis.

Main Results:

• A cutoff of 10 cm on the AST showed 88.57% alteration in PVOD+ patients versus 60.53% in PVOD- patients (p=0.013).
• Significant differences in mean AST distance were found between PVOD+ and control groups (4.35 vs 20 cm, p<0.05), and between PVOD+ and PVOD- groups (9 vs 20 cm, p<0.05).
• The AST demonstrated 88% sensitivity and 41% specificity for PVOD detection with a 10 cm cutoff, yielding an Odds Ratio of 9.7 (p<0.001).

Conclusions:

• Post-viral olfactory dysfunction, including COVID-19 related cases, is a prevalent cause of olfactory loss.
• The Alcohol Sniff Test is a promising, accessible tool for early screening of PVOD in patients with flu-like symptoms.
• Early identification via AST can facilitate prompt interventions, potentially reducing the incidence of persistent hyposmia.