The pragmatic role of nasal cytology: A point-of-care testing to implement precision medicine in clinical practice

Background: Precision medicine is an up-to-date strategy aimed at individualizing precise pathophysiological mechanisms. Thus, precision medicine is the basis for personalized medicine, inasmuch as it seeks to define the most appropriate treatment for each patient. Nasal cytology requires only an optical microscope, stains, glasses, and nasal cytology curettes. The procedure may last very few minutes using quick staining and, therefore, it can be considered a reliable point-of-care test in the office setting. Methods: Cross-sectional study that included 5030 outpatients with nasal disorders: 2612 males and 2418 females, with a mean age of 36.8 ± 17.1 years, who were attended to within a 5-year period. The patients were subdivided according to skin prick-test and nasal cytology results into subjects with allergic rhinitis or non-allergic rhinitis. Cellular forms were further subdivided based on their cytotype: NARNE (> 50% of neutrophils with absence of spores and bacteria); NARES (> 20% of eosinophils); NARMA (> 10% of mast cells); and NARESMA (> 20% of eosinophils and > 10% of mast cells). Results: 453 subjects (9%) had negative nasal cytology, 1056 (21%) had allergic rhinitis, 538 (10.7%) had NARES, 493 (9.8%) had nasal polyposis, 251 (5%) had rhinosinusitis, 221 (4.4%) had NARESMA 201 (4%) had infectious rhinitis, 131 (2.6%) had NARMA, 89 (1.8%) had NARNE, with the remaining subjects having a miscellaneous inflammatory/infectious profile. Conclusions: Nasal cytology provides quick information about phenotype and endotype and can be repeated during follow-up to assess post-treatment changes.