The validity of the thread test for evaluating nasal secretion in nasal allergy.

The volume of nasal secretion is so small that it is difficult to measure. We placed a thread on the anterior surface of the inferior turbinate to measure the volume of nasal secretion in normal subjects and patients with nasal allergy. In 24 normal subjects, the average nasal secretion amounted to 1.09 microliter/min. In 48 patients with nasal allergy, the volume of nasal secretion (1.94 microliter/min) decreased significantly after nasal spraying: the subjective symptoms of sneezing, rhinorrhea, nasal obstruction, inconvenience in daily life and the objective signs such as watery rhinorrhea abated. The thread test results showed a good correlation with the above items in a quantitative analysis. The thread test is a simple way to measure a small volume of nasal secretion, and a useful indicator of the severity of watery rhinorrhea in patients with nasal allergy.