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Barcelona Olfactory Test - 8: validation of a new test on Spanish population during COVID-19 pandemic

Rojas-Lechuga MJ1,2,3, Ceballos JC1,2, Valls-Mateus M4, Mackers P5, Izquierdo-Domínguez A2,6,7, López-Chacón M1,2,3, Langdon C1,2,3, Mariño-Sánchez F8, Valero J9, Mullol J1,2,3*, Alobid I1,2,3,7*

1Rhinology Unit & Smell Clinic, Department of Otorhinolaryngology, Hospital Clinic, Universitat de Barcelona, Spain
2Clinical and Experimental Respiratory Immunoallergy, IDIBAPS, Barcelona, Spain
3CIBER of Respiratory Diseases (CIBERES), Spain
4Department of Otorhinolaryngology, Hospital Universitari Son Espases, Mallorca, Spain
5Department of Otorhinolaryngology, Hospital del Mar, Barcelona, Spain
6Department of Allergology, Consorci Sanitari de Terrassa, Barcelona, Spain
7Unidad Alergo Rino, Centro Médico Teknon, Barcelona, Spain
8Rhinology and Skull Base Surgery Unit. Otorhinolaryngology Department, Hospital Ramón y Cajal, Madrid, Spain
9Departament de Fisicoquímica. Facultat de Farmàcia. Universitat de Barcelona, Spain.
*These authors equally contribute as senior and corresponding authors

J Investig Allergol Clin Immunol 2022; Vol. 32(4)
doi: 10.18176/jiaci.0824

Background: In daily clinical practice, most smell tests are difficult to implement due to their long duration. The aim of the present study was to develop and validate a short, easy to perform, and reusable smell test to be implemented during COVID-19 pandemic.
Methods: 120 healthy adults and 195 patients with self-reported olfactory dysfunction (OD) were included. Barcelona Olfactory Test (BOT-8) was used for detection, memory/recognition, and forced-choice identification. In addition, rose threshold test and VAS was performed. The Smell Diskettes Olfaction test (SDOT) was used for correlation in healthy volunteers, and UPSITTM for patients with OD to stablish an anosmia and hyposmia cut-off point. Considering COVID-19 pandemic disposable cotton swabs with odorants were compared with the original test.
Results: In healthy population, BOT-8 mean scores for detection was 100%, memory/recognition was 94.5% (SD=1.07), and identification was 89.6% (SD=0.86). In OD patients was 86% (SD=32.8), 73.2% (SD=37.9) and 77.1% (SD=34.2), respectively. BOT-8 demonstrated good test–retest reliability with a 96.7% of observed agreement and a quadratic kappa of 0.84 (p<0.001). Strong correlation was observed for BOT-8 with SDOT (r=0.67, p<0.001) and UPSITTM (r=0.86, p<0.001). Disposable cotton swabs showed an excellent agreement with a kappa of 0.79 compared to the original test. The cut-off point for anosmia was ≤ 3 (AUC=0.83, Se= 0.673, Sp=0.993).
Conclusions: BOT-8 offers an efficient and fast method to be used in clinical routine to assess the smell threshold, detection, memory, and identification. Disposable cotton swabs with odorants are a useful and safe method during the COVID-19 pandemic.

Key words: Olfaction, Smell test, Smell loss, Anosmia, COVID-19