[Saccharin test for the study of mucociliary clearance: reference values for a Spanish population].

OBJECTIVE Mucociliary transport is an important defense mechanism for the airways. The aim of this study was to establish reference values for nasal mucociliary clearance time (MCT) by means of the saccharin test. SUBJECTS AND METHODS A cross-sectional, descriptive, observational study was performed. The variables studied were nasal MCT, age, and sex. We included 249 healthy nonsmokers (134 male and 115 female subjects) aged over 10 years and stratified the sample by age. To establish reference values, percentiles were calculated and lower and upper limits of normal were established at percentiles 2.5 and 97.5, respectively. The association between nasal MCT and the main study variables was then investigated along with the reproducibility of the test. RESULTS The following values for nasal MCT were obtained for the sample as a whole: mean (SD), 17.17 (8.43) minutes; median (interquartile range), 16 minutes (12-20 minutes), indicating that the central 50% of the sample fell within this 8-minute range; and maximum and minimum values of 4 to 54 minutes (range, 50 minutes). The upper and lower limits of normal were 6 and 36 minutes, respectively. In addition, it is noteworthy that only 6 subjects had a nasal MCT longer than 36 minutes. No significant differences between male and female subjects were found. Nasal MCT showed a positive correlation with age (rho=0.324; P=.0001). No significant differences were observed in the reproducibility test (P=.208). CONCLUSIONS In addition to facilitating reliable data on mucociliary function, the saccharin test is easy to do, inexpensive, and reproducible. The data obtained from this study should allow the results of this test to be correctly interpreted for a given subject's age and so facilitate its use in clinical practice.