Finger thermometry in the assessment of subjects with vibration-induced white finger.

The measurement of finger skin temperature (FST) is one of the most commonly used methods for evaluating the response of the digital vessels to cold stimulation. In well-controlled experiments a significant correlation has been observed between FST and digital blood flow over a wide range of water temperatures. On the contrary, FST in air is considered an inadequate index of digital skin circulation since, at a given ambient temperature, FST depends not only on the rate of blood flow through the digit but also on environmental conditions. Despite these limitations, FST recording after a cooling procedure has been used in surveys of vibration-induced white finger (VWF), and a delayed finger rewarming time has been proposed as an indicator of digital vasospasm in workers with VWF. Finger skin thermometry can differentiate between VWF groups and healthy groups, but it is unsuitable for diagnosing Raynaud's phenomenon on an individual basis. The thermometric method has good specificity but its sensitivity is lower than that of plethysmographic techniques. FST after cold provocation may be considered a useful screening test in field studies, while more sensitive methods should be employed to confirm VWF symptoms in individuals objectively, especially for insurance compensation purposes.