**2.2 Microscopic observation**

The analysis of the sample of cytology material mounted on the slide is done with an optical microscope equipped with multiple objectives, each with different magnification power.


**Table 1.** *Classification of rhinosinusitis.*

#### *Rhinosinusitis*

Initially, a general inspection of the material is carried out with a lower magnification objective (4×/0.10). Once the most significant part of the sample has been identified, the evaluation will be carried out with increasingly powerful objectives to exploit the maximum possible magnification (100×/1.25) with the help of oil for immersion.

In accordance with the guidelines of the Italian Academy of Nasal Cytology (AICNA), for each sample taken, we analyze at least 50 fields at maximum magnification (100×/25) by counting the different types of cells found. The observed data are then shown in a **Table 1**.
