Test-retest reliability of the olfactory detection threshold test of the Sniffin' sticks

The aim of the present study was to investigate the test-retest reliability of the olfactory detection threshold subtest of the Sniffin' Sticks test battery, if administered repeatedly on 4 time points. The detection threshold test was repeatedly conducted in 64 healthy subjects. On the first testing session, the threshold test was accomplished 3 times (T(1) = 0 min, T(2) = 35 min, and T(3) = 105 min), representing a short-term testing. A fourth threshold test was conducted on a second testing session (T(4) = 35.1 days after the first testing session), representing a long-term testing. The average scores for olfactory detection threshold for n-butanol did not differ significantly across the 4 points of time. The test-retest reliability (Pearson's r) between the 4 time points of threshold testing were in a range of 0.43-0.85 (P < 0.01). These results support the notion that the olfactory detection threshold test is a highly reliable method for repeated olfactory testing, even if the test is repeated more than once per day and over a long-term period. It is concluded that the olfactory detection threshold test of the Sniffin' Sticks is suitable for repeated testing during experimental or clinical studies.