Your health care provider will likely ask you about your symptoms and ask whether you've had a recent cold, suffer from allergies, smoke regularly or are exposed to secondhand smoke as these factors may contribute to sinus infection.
During a physical exam, your health care provider may test for sinus infection by:
Feeling for tenderness in the sinus area.
Shining a light into your nasal passages to look for inflammation.
Ruling out nasal polyps or other deformities.
If the results of the physical exam are vague or symptoms persist, you're health care provider may order imaging studies or laboratory tests such as:
A computed tomography (CT) scan to confirm sinus infection.
Blood tests to rule out other conditions associated with sinus infection like an immune deficiency disorder or cystic fibrosis.
Cultures (special blood tests) to detect bacterial or fungal infection.
A biopsy to determine the health of the cells lining the nasal cavity.
If you have chronic sinus infection (lasting 8 weeks or more) or recurrent sinus infection (several separate attacks within a year), further laboratory tests may be used to find an underlying disorder. This may involve sweat chloride tests for cystic fibrosis, ciliary function tests, blood tests for HIV, or other tests for immunodeficiency, allergy testing, or nasal cytology (checking the cells in the nasal secretions).