Laboratory parameters of the 1st order – obligatory laboratory tests.
- Inflammatory diagnostics – in case of fever above 38.3 °C, severe symptoms, increase of symptoms during the course of the disease, threatening complications
- CRP (C-reactive protein); more appropriate is the determination of procalcitonin, which allows some differentiation of bacterial and viral infections.
- Leukocytes (white blood cells).
Note: Elevations in CRP correlate with radiographic findings and clinical severity of infection.
Laboratory parameters 2nd order – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification.
- Microscopy, culture procedures, germ identification if necessary and resistance testing (in case of resistance to therapy)Indications: In acute rhinosinusitis (ARS) dispensable and only to be considered if a successful therapy within 48-72 h leads to no improvement or in underlying diseases associated with immune deficiency (consensus decision of the S2k guideline); if necessary, also in purulent secretion (purulent secretion).
- Allergy diagnostics (61% showed a positive reaction)Note: Routine allergological testing should not be used in the diagnosis of acute rhinosinusitis (ARS) (strong consensus, 7/7)indications [S2k guideline]:
- In etiologically unexplained chronic rhinosinusitis with nasal polyps (CRSsNP), allergologic testing may be performed or should be performed if there is history or clinical evidence of an allergic etiology.
- In etiologically unexplained postoperative recurrence of CRSsNP, allergic testing should be performed.
- Small blood count
- Differential blood count
- CANCA (antineutrophil cytoplasmic antibody with cytoplasmic fluorescence pattern) – typical laboratory parameter indicative of granulomatosis with polyangiitis (GPA), formerly Wegener’s granulomatosis (progressive respiratory granulomatosis).
- Cytology and nasal mediator determination (in individual cases of eosinophilic and neutrophilic rhinitis).
- Saccharin test – in cases of suspected primary ciliary dyskinesia (genetic dysfunction of ciliary-bearing cells, especially respiratory ciliated epithelium, characterized by chronic disease of the upper and lower respiratory tract).
- Nasal biopsy – collection of tissue samples from the nasal mucosa (indication: suspected malignancies, granulomatoses and invasive fungal diseases).
