Validation of olfactory threshold testing methods

In patients with chemosensory complaints, a head-to-head comparison of unilateral olfaction threshold testing with the Phenyl Ethyl Alcohol Smell Threshold Test (PEA) and the OLFACT-RL Odor Threshold Test (OLFACT-RL) was undertaken. The charts of 23 consecutive patients presenting with chemosensory complaints seen at the Smell and Taste Treatment and Research Foundation were reviewed and information extracted per Institutional Review Board guidelines. All patients had undergone olfactory testing with the PEA test and the OLFACT-RL test in accordance with their published administration manuals. Using Spearman correlation coefficients to measure the statistical correlation between tests, we found evidence of a correlation between PEA and OLFACT-RL values on the left side only, overall (r = 0.49, p = 0.0184); in those who had hyposmia and did not have anosmia (r = 0.42, p = 0.0668); in those who did not have burning mouth syndrome (r = 0.46, p = 0.0304); and in those who did not have dysosmia (r = 0.47, p = 0.0553). There is no evidence of a correlation on the right side. The correlation for the left nostril suggests that these tests may be interchangeable. However, lack of correlation with the right nostril requires further investigation.