Oral Temperature Measurement: Why Under the Tongue?

Placing a thermometer under the tongue (sublingual) is a standard, reliable method because:

1. Rich vascularity: The lingual arteries provide rapid heat exchange, reflecting core temperature.
2. Accessibility: Easy, non-invasive, and comfortable for most patients.
3. Accuracy: Correlates well with pulmonary artery and esophageal temperatures when done correctly.
4. Standardization: Widely adopted, enabling consistent comparisons.

Tips for accuracy: Wait 15–30 minutes after eating/drinking hot/cold substances; keep mouth closed; breathe through nose. Avoid in patients with oral lesions, seizures, or inability to cooperate.