Sputum Eosinophils

What is the Sputum Eosinophils test?

The Sputum Eosinophils test is a diagnostic procedure used to measure the number of eosinophils—a type of white blood cell—in a person's sputum (mucus coughed up from the lungs). Eosinophils are involved in allergic reactions and are often elevated in conditions such as asthma or eosinophilic bronchitis. Analyzing sputum for eosinophils helps assess airway inflammation and can guide treatment plans, especially in patients with chronic respiratory diseases.


Why is this test done?

This test is commonly used in the diagnosis and monitoring of asthma and other eosinophilic lung diseases. It helps determine if inflammation in the airways is driven by eosinophils, which in turn can guide the use of corticosteroids or other anti-inflammatory medications. The presence of eosinophils in sputum may also indicate a heightened allergic response.


How is the test performed?

The patient is asked to produce a deep cough to expel sputum from the lungs into a sterile container. In some cases, saline may be inhaled to help induce sputum production. The collected sputum is then stained and examined under a microscope to identify and count the eosinophils. The test is non-invasive and typically done in a clinical setting.


What do the results mean?

Elevated eosinophils in the sputum suggest eosinophilic inflammation, commonly associated with asthma, allergic bronchopulmonary aspergillosis, or chronic eosinophilic pneumonia. Normal or low levels may suggest non-eosinophilic inflammation, which requires different management. The results guide therapeutic decisions, especially in tailoring inhaled corticosteroid doses.


Are there any precautions or preparations required?

Generally, there are no specific preparations needed before the test. However, patients should follow instructions on medication use prior to the test, as some drugs may affect eosinophil levels. It is also important to avoid contamination with saliva to ensure accurate results.