{'fraction_non_alphanumeric': 0.05309734513274336, 'fraction_numerical': 0.01407884151246983, 'mean_word_length': 5.296202531645569, 'pattern_counts': {'":': 0, '<': 3, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Truths and fakes in the smell terminology during the COVID‐19 outbreak

Lechien et al. evaluate the progression of OD by ‘objective olfactory evaluations’ consisted of the Sniffin’ Sticks test. Nevertheless, this smell test is subjective as are most of the used olfactometries. This mistake is not uncommon and several authors refer to ‘Sniffin’ Sticks’ as an objective evaluation [2, 3]. In point of fact, an objective test is one that detects changes in central neural system and does not require patient ́s collaboration [4]. Only olfactory evoked potentials, electro-olphatogram, functional magnetic resonance imaging and positron emission tomography are objective tests to evaluate OD. Subjective evaluations of OD depend on patient collaboration, culture, environmental factors, medical history, explorer and type of study [4]. A large number of psychophysical olfactometric subjective tests are available such as ‘University of Pennsylvania Smell Identification Test’ (UPSIT), ‘Smell Identification Test,’ ‘Barcelona Smell Test-24 (BAST-24),’ ‘Connecticut Chemosensory Clinical Research Center’ (CCCRC), ‘Japanese odour stick identification test’ (OSIT (11)), ‘Scandinavian Odor Identification Test’ (SOIT, (12)), ‘Smell Diskettes’ or ‘Sniffin’ Sticks,’ amongst others [2, 4, 5]. Although all of them can be used, subjective smell tests must be well validated for the assessed population due to cultural variability in odorant detection. If a smell test has not been properly validated, it should not be used in a given population. Data from Sniffin’ Sticks test are reported in publications as ‘TDI score,’ which is derived from the sum of the results obtained in those three test [6]. Previous work, in population from 6 countries, established the term ‘hyposmia’ for subjects with a TDI score <31 and ‘anosmia’ for subjects with TDI score <16 [6, 7]. However, cut-off values might depend also on the population studied. In Lechien et al. [1] article, odour dysfunction was evaluated using Sniffin ́s Sticks. The authors classified the results into 3 categories: normosmia (score 12–16), hyposmia (score 9–11) and anosmia (<9). However, to the best of our knowledge, there are no studies validating this classification. Using non-validated classifications might bias results when comparing with other studies, whilst the use of incorrect cutoff values can lead us to wrong conclusions. As we describe, the results of the Sniffin’ Sticks test should be presented as ‘TDI score.’