The intranasal Schirmer test: a preliminary study to quantify nasal secretion

Adequate secretion of the nasal mucosa is essential for normal nasal physiology. A "dry" nose is a frequent complaint of ENT patients. Measurement of secretion is currently impossible because of the absence of a recognized test. The aim of the present study was to investigate the feasibility of an intranasal Schirmer test in a large number of patients and to define standard values for nasal secretion. The test population comprised 159 healthy, non-smoking volunteers and 30 healthy smoking volunteers. All subjects were examined by nasal endoscopy for anatomic or mucosal disease. A Schirmer test strip was placed on both sides of the mucosa of the anterior nasal septum by anterior rhinoscopy. After 10 min in standardized conditions, the strip was removed and the wetted distance was measured. Active anterior rhinomanometry (ARR) and acoustic rhinometry (AR) were later performed. In the non-smoking group (n = 159), the median wetting distance of the test strip was 10.3 mm (range 3.6-35.0 mm). Age, gender, nasal geometry, and flow (according to ARR and AR) had no significant influence on nasal secretion. The test for normal distribution was negative. In the smoking group (n = 30), the median wetting distance was 8.4 mm (range 2.5-28.0 mm), significantly shorter than the wetting distance in the non-smoking group (p < 0.05). The Schirmer test offers a practical method to quantify mucosal humidification. The test is inexpensive and well tolerated by patients. In healthy people, wetting distances from 6 to 18 mm are considered normal.