A critique of a UK standardized test of finger rewarming after cold provocation in the diagnosis and staging of hand–arm vibration syndrome

Background Accurate diagnosis and staging of hand–arm vibration syndrome (HAVS) is important in health surveillance of vibration‐exposed workers and the substantial number of related medico‐legal cases. The measurement of the rewarming rate of fingers after cold provocation to the hands (CPT) has been suggested as a useful test in diagnosing HAVS. Aim To investigate the diagnostic value of a standardized version of the CPT test using a 15°C cold challenge for 5 min applied in the recent compensation assessment of UK miners. Methods Analysis of a subset of UK miners assessed at our unit, together with data from a small repeatability study of the standardized CPT in normal subjects. Results Rewarming time in the CPT was significantly lower in those subjects classified as vascular Stockholm stage 0 compared with Stockholm stages 1–3 combined, but did not discriminate between the stages of abnormality. Using the suggested cut‐off in the CPT test, the sensitivity and specificity were calculated as 43 and 78%, respectively. Receiver operator characteristic analysis suggested that the rewarming time of highest accuracy gave a sensitivity of 66% and specificity of 59%. In 10 miners who reported unilateral hand blanching, there was no significant difference in CPT measurements between blanching and non‐blanching hands. Repeat CPT measurements in normal subjects suggested mean differences of 52 and 107 s for each hand, and the Bland–Altman coefficient of repeatability was ∼600 s for all fingers. Conclusion Single application of this standardized CPT test may have limited value in diagnosing the vascular component of HAVS in an individual.