CPT® Code 89190

A nasal smear for eosinophils is a laboratory procedure designed to identify the presence of eosinophils, which are a specific type of white blood cell involved in the body's immune response. This procedure is particularly relevant in the context of diagnosing allergic conditions, such as allergic rhinitis. During the test, nasal secretions are collected through a swab inserted into each nostril, targeting the area near the septum and nasal floor. The swab is held in place for a duration of 15 to 30 seconds, or until a cough reflex is elicited, ensuring an adequate sample is obtained. Alternatively, the patient may be instructed to blow their nose into a piece of waxed paper or cellophane to collect the secretions. Once collected, the nasal secretions are placed on a glass slide and subjected to a staining process. This staining allows for the visualization of eosinophils when the slide is examined under a light microscope. The laboratory technician counts the number of eosinophils present in the sample and reports the findings, which can aid in confirming a diagnosis of allergic rhinitis or other related conditions.