Objectives: In order to establish an international standard of cold provocation test in the assessment of vibration-induced white finger (VWF) disease, an ISO-working group tentatively created the DIN ISO 14835-1. Based on this new standard, previously existing testing conditions had to be modified. Since a comparison of current and previous evaluation procedures is necessary for both the individual assessment and the performance of metaanalyses, the revision and validation of criteria for the examination of the cold provocation tests are appropriate and necessary.
Methods: Twenty-one individuals suffering from VWF disease whose disorder was accepted as an occupational disease underwent the cold provocation test on two successive days following a 2- and a 5-min-long exposure to the cold. As a benchmark for classification as 'normal' or 'pathological', the 15-min mark after a 2-min-long exposure was chosen. A skin temperature of 28 degrees C was selected for discrimination between 'non-pathological' (at least 28 degrees C) and 'pathological' test results.
Results: It could be shown, that exposures to cold water (12 degrees C) over 2 and 5 min lead to similar rewarming profiles, who differ in median systematically by 1 degrees C. A modification of the former classification rule should be considered. After a 5 min exposure, the classification criterion can be based on the temperature assessments measured after 20 min; alternatively the cut point can be reduced from 28 to 27 degrees C while maintaining the previous assessment time of t = 15 min.
Conclusions: The shown results represent the first attempt of modifying the previous classification criteria of the cold provocation test within the scope of the VWF disease. In view of the described problems of the study design there is no doubt that continuing modifications and their validation on the base of larger collectives groups are necessary.