Tuberculine reaction measured by infrared thermography

•First paper devoted to tuberculine reaction measurement based on thermal imaging.•There is good agreement in area length of tuberculin reaction between visual and thermographic evaluation.•Automatic generation of positive and negative results of the tuberculin skin test evaluated by infrared imaging.

SettingThe infection with Mycobacterium tuberculosis gives a delayed immune response, measured by the tuberculine skin test. We present a new technique for evaluation based on automatic detection and measurement of skin temperature due to infrared emission.Design34 subjects (46.8 ± 16.9 years) (12/22, M/F) with suspected tuberculosis disease were examined with an IR thermal camera, 48 h after tuberculin skin injection.ResultsIn 20 subjects, IR analysis was positive for tuberculine test. Mean temperature of injection area was higher, around 1 °C, for the positive group (36.2 ± 1.1 °C positive group; 35.1 ± 1.6 °C negative group, p < 0.02 T test for unpaired groups).ConclusionIR image analysis achieves similar estimation of tuberculin reaction as the visual evaluation, based on higher temperature due to increased heat radiation from the skin lesion.