2022 Volume 53 Issue 3 Pages 178-182
Two types of olfaction tests are currently covered by health insurance in Japan : the “T&T olfactometry” and the “intravenous olfactometry.” The intravenous olfactometry proposed in 1960 is one of the longest-established olfaction tests in the world and is a unique method that injects odorants into the medial cubital vein. On the other hand, the “sniffing” olfaction test has long lacked a standard test in comparison to the hearing test which was standardized in 1956, and has been conducted in different ways at different facilities. In 1971, research groups were formed to establish a standardized olfaction test and in 1973, an article on reference odors familiar to the Japanese population was published. In 1978, T&T olfactometry was announced and for more than 40 years since then, it has been used as an insurance-covered olfaction test along with the intravenous olfactometry. “Jet Stream olfactometry” was announced in 1996 to reduce air contamination and to quantify test odorants, which were problems with the T&T olfactometry, but it is currently unavailable due to the discontinuation of the test equipment. In 1984, an olfaction test using odorant-microencapsulation technology named “UPSIT” was announced in the US to simplify the testing procedure and to prevent air contamination. In 2006, the “odor stick identification test” was announced in Japan, and in 2008, a revised version named “Open Essence” became available. Both tests use odorant-microencapsulation technology; the former uses odorant-microencapsulated sticks which are applied to paraffin paper each time, the latter uses odorant-microencapsulated-printed cards.
These olfactory tests are usually used in combination in clinical practice. However, the results of olfactory tests often do not match with patients’ subjective olfactory symptoms, and to evaluate this, visual-analogue-scale and “self-administered odor questionnaire” are also used in olfactory clinics. In recent years, with the increase of eosinophilic sinusitis and COVID-19, olfactory care has gained more attention and importance.
